Definition of monitor in English:



  • 1A device used for observing, checking, or keeping a continuous record of something.

    ‘a heart monitor’
    • ‘A cheaper and even better solution is to install a depth monitor inside the operator cab.’
    • ‘These monitors contain built-in blood-sampling devices that take your blood from areas other than your finger, such as your arm, abdomen or thigh.’
    • ‘The patient may be placed on a cardiac monitor to observe the heart rate and rhythm at all times.’
    • ‘The figure you arrive at is your target training heart rate, which you can observe on the monitor while exercising.’
    • ‘Of all the monitors used in the operating room, pulse oximetry has been shown to have the highest yield in the early detection of life-threatening events.’
    • ‘The ion and electron monitors were turned on several months ago in preparation for their role during solar wind collection.’
    • ‘Put him on an electronic monitor and let him stay back at his house where he's been for the last year.’
    • ‘Alternatively, you can have a monitor fitted that records your heart rhythm over a 24-hour period.’
    • ‘During the procedure, monitors constantly check your heart, blood pressure and oxygen use.’
    • ‘Electronic body-fat monitors are widely available and rapidly dropping in price.’
    • ‘The same units are used for electronic blood pressure monitors.’
    • ‘The refrigerator should be equipped with an electronic monitor and an alarm to alert staff members when temperatures are outside acceptable limits.’
    • ‘These shortcomings underscore the appeal of so-called continuous glucose monitors, which check blood sugar levels scores of times a day.’
    • ‘The company's product line includes sleep-apnea monitors, electrocardiograph devices, and electronic stethoscopes.’
    • ‘As part of his parole, the electronic monitor around his ankle keeps track of his comings and goings.’
    • ‘Pace also hinted that it was contemplating diversification into healthcare products such as heart or insulin monitors and security products for homes and businesses.’
    • ‘He looked up to where the doctor was checking over the heart monitor.’
    • ‘I remember reading about a study where researchers hooked heart monitors up to various NASCAR drivers while they took practice laps around the track.’
    • ‘A heart monitor clicked like a clock next to the bed.’
    • ‘Eventually I began to wonder if the baby monitor was picking up the newborn from across the street.’
    detector, scanner, recorder
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    1. 1.1A person operating a monitor.
      ‘a monitor aboard the vessel said he had measured radiation levels ten times the normal level’
      • ‘The machine monitor who has worked for the company for nearly 39 years said the news was a shock.’
    2. 1.2A person who observes a process or activity to check that it is carried out fairly or correctly, especially in an official capacity.
      ‘the deployment of troops went ahead despite the shooting down of an EC monitor's helicopter’
      ‘the independent judicial monitor’
      • ‘The task at hand now for international peace monitors is ensuring that the process gets back on track.’
      • ‘One approach would be to have independent monitors undertake multifaceted analysis of a firm's pro bono practice.’
      • ‘The insurance company might allow an independent monitor to scrutinise the demutualisation process on behalf of policyholders.’
      • ‘It appeared to be in line with some previously published estimates by independent monitors.’
      • ‘The education board sent monitors to schools to make sure that the ceremonies are conducted according to protocol.’
      • ‘They have asked for the hundreds of independent monitors to be allowed inside polling stations, a request approved by the judiciary but rejected by the electoral commission.’
      • ‘‘There might be international observers but not monitors, and they will have no role in supervising elections,’ Sorour added.’
      • ‘They are asking for election monitors and observers to be sent to Gamelonia, of course all expenses to be borne by us.’
      • ‘A court-appointed monitor has been overseeing operations under a deferred-prosecution deal.’
      • ‘He reiterated the country's stand that the country should observe UN resolutions and allow the arms monitors in for inspection.’
      • ‘To add to the saturation coverage, a number of independent civil rights monitors will observe events.’
      • ‘And Pittsburgh education officials recently began placing independent monitors in each school after several cheating incidents.’
      • ‘Under the agreement reached last year, the software giant was to appoint an independent monitor to check it was complying with the EC demands.’
      • ‘I headed over in his direction as a monitor scolded Ty to sit down.’
      • ‘Like all players in the electoral process, monitors must also abide by the rules and regulations of the game.’
      • ‘Independent monitors will calculate the scores and the top-scoring driver will represent Ireland at the Grand final in Sweden on September 16 and 17.’
      • ‘So this time around, city officials hope election monitors will pronounce the process glitch-free.’
      • ‘The certified factories must agree to unannounced inspections by accredited, independent monitors.’
      • ‘Paper ballots can be switched, and that is the purpose of having observers and monitors who witness the physical tallying.’
      • ‘When the tribunals begin, foreign experts can act as observers and monitors.’
      observer, watchdog, overseer, invigilator, supervisor
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    3. 1.3A person who listens to and reports on foreign radio broadcasts and signals.
      ‘radio monitors reported they heard the pilot say he was heading for Paris’
      • ‘Intelligence monitors are picking up less terror threat talk than a year ago, the Homeland Security Secretary said Thursday.’
  • 2A television receiver used in a studio to select or verify the picture being broadcast from a particular camera.

    ‘the playback can be displayed on an external television screen or monitor’
    • ‘So that the viewer always receives the proper images for the corresponding eye, a camera affixed to the monitor records the position of the head.’
    • ‘Most people equate visualization with sitting in front of a bank of monitors watching several visual feeds.’
    • ‘Now I place it under a television camera, and that is fed to a television monitor in front of Howard.’
    • ‘All the doors will be bullet, heat and shock proof and have digital locks while closed circuit television monitors will help ensure that only authorised staff gain entrance.’
    • ‘During filming, the technical experts worked long and hard to get 30 monitors in a TV studio to show the same picture.’
    • ‘There is a section where images that have been recorded in real time are played back on four monitors.’
    • ‘Each of 40 cheap television monitors atop rickety tables shows a resident of the notorious ghetto talking directly into the camera.’
    • ‘Several friends joined us in such a room, which was outfitted with a large monitor and microphones.’
    • ‘Products which could use the display include camera viewfinders, projectors, monitors, television sets and headsets for the military, medical and simulation markets.’
    • ‘The room has several wooden chairs with television monitors playing footage of moving clouds.’
    • ‘My cell was in the corner of the room, and on the opposite wall was a sea of television monitors.’
    • ‘Within lay batteries of television monitors showing live feed from almost a hundred satellites, some of them so powerful that they could track the progress of a single ant on the ground.’
    • ‘He watched the monitors before him observing the activity going on in the building.’
    • ‘Instead, in one corner there is the monitor of a closed-circuit television showing the area in front of the entrance, the waiting room, the anteroom and the room itself.’
    • ‘I hit record, check the monitor and wait till I see the tape roll.’
    • ‘He looked up at the television monitor and watched as the crewman performed several tests to answer that question.’
    • ‘Backstage, the producer is barking instructions into a headset while pacing and gesturing wildly in front of a bank of television monitors.’
    • ‘He pressed a few buttons on the console and an image appeared on one of the television monitors.’
    1. 2.1A screen which displays an image generated by a computer.
      • ‘You are staring at the your monitor waiting for the image to download.’
      • ‘Intraoperative magnetic resonance images are displayed on monitors within the gap.’
      • ‘He had just purchased a new computer with a touch screen monitor, and he needed help installing the software.’
      • ‘If you have a mouse with a scroll wheel you can change the size of fonts and images displayed on your monitor screen with a single click.’
      • ‘Alone at his desk, the detective glances up at the black login screen displayed on the computer monitor.’
      • ‘Computer monitors generally have a refresh rate of at least 60 Hz, meaning the screen is refreshed at least 60 times a second.’
      • ‘The radar operator was watching carefully as the blip on his monitor representing the Renegade crawled into the system.’
      • ‘I once called the computer store where I bought my computer because my monitor was not working.’
      • ‘The robust demand is expected to continue into this year on rising shipments of laptop computers, LCD monitors and LCD TVs, Hsieh said.’
      • ‘The commander looked at the monitor showing vital information about the pilots, cargo and condition of the tubes.’
      • ‘The big monitor in the center was all black, except for some green text splashed across the screen.’
      • ‘Within seconds, vital operational data can be displayed on the large wall display screens or individual computer monitors.’
      • ‘The race is on at home and in the office to replace large and heavy boat anchor PCs and their monitors with notebook computers.’
      • ‘All over the room, men sat stationed at their monitors, reporting the status of the enemy compounds to their officers.’
      • ‘If they use a flat-screen monitor, they can raise or lower the apparatus that holds it.’
      • ‘Is the cable from the monitor connected to the computer's video card connector?’
      • ‘After the video is scaled it is changed into a digital format recognized by the video card and then it is displayed on your monitor.’
      • ‘Flat-panel screens found their biggest niche in laptops, but now they're replacing desktop monitors and even television sets.’
      • ‘The semiconductor devices can be used in things such as TV screens, computer monitors, medical imaging and digital cameras.’
      • ‘A 17-inch flat screen monitor that displays distortion-free images with a high degree of clarity makes the home theatre system complete.’
      screen, vdu, visual display unit
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    2. 2.2A loudspeaker used by performers on stage to hear themselves or in the studio to hear what has been recorded.
      ‘I was amazed at the quality of the sound coming from the monitors’
      • ‘The 896HD's outputs fed both the quad mix to the house and the in-ear monitors used for the stage.’
      • ‘Loud stage monitors can make the situation worse, because there's a constant slap delay when their sound bounces off of the back wall and heads back into the house.’
      • ‘The Gryphon Trio also uses techniques well outside conventional chamber music, employing a click track that the musicians can hear from their in-the-ear monitors.’
      • ‘It's harder to hear through the monitors, and you tend to sing louder, and it's more direct, for sure.’
      • ‘A few minutes later, he found himself in the wings of the stage, with one of their sound guys, Marv, hooking up his microphone and ear monitors.’
      • ‘The musician's stage contains no wedge monitors and very few microphones.’
      • ‘The band listens on wedge monitors, but Brown uses a Shure PSM600 ear monitor in one ear.’
      • ‘She doesn't even explain whether the black armband she's sporting is a mark of respect or an electronic doohickey for her earpiece monitor.’
  • 3A school pupil with disciplinary or other special duties.

    ‘he was a school monitor and a choir boy’
    • ‘There are no teachers or hall monitors walking around, thankfully.’
    • ‘I have to get going - they're about to send out the campus monitors to enforce lights out.’
    • ‘The approach taken by some schools to introduce pupils as monitors had proved effective at tackling vandalism on buses.’
    • ‘Rebecca remembers that the teacher would always assign a student that would be a monitor during lunch.’
    • ‘Since the first grade he has been always an excellent pupil and the class monitor.’
    • ‘This must have been nearly as shocking as that dark day lost in history when she was demoted from her position as milk monitor at primary school.’
    • ‘The hall monitors stopped me, but when I told them of my destination, they let me go.’
    • ‘By the time Sam entered the front door through a pair of metal detectors, he half-expected to find the student hall monitors equipped with machine guns.’
    • ‘I sighed in relief, grateful I hadn't run into one of the stricter hall monitors.’
    • ‘I'm sorry, but it's my duty as hall monitor to catch those who are skipping and report them.’
    • ‘The monitor in the hall tried to stop us and ask for a hall pass, but we both ran past her and out to my car.’
    • ‘The school has two full-time dedicated student monitors who, according to the school, ‘supervise all activities of the students’.’
    • ‘After she'd debriefed him, she had gone to Noelle's classroom, dodging the hall monitors on the way.’
    • ‘She shook her head and leaned against him as they walked out of the school, totally unnoticed by teachers and hall monitors.’
    • ‘He began meandering down the halls, as was his duty as a monitor, trying to forget about the event that had just transpired.’
    • ‘She knew she was supposed to be in homeroom, but she didn't see any hall monitors ready to give her detention.’
    • ‘I pulled her quick into the restroom, before a hall monitor could come and give us demerits.’
    • ‘The hall monitors were out, leaning against the wall and making sure that the students stayed in the areas outside of the ongoing classes.’
    • ‘Yard monitors and lunch time supervisors can be trained to watch for signs of bullying.’
    • ‘Classroom monitors hand out the pastels and Manila paper for the warm-up exercises.’
    prefect, praepostor
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  • 4A large tropical Old World lizard with a long neck, narrow head, forked tongue, strong claws, and a short body. Monitors were formerly believed to give warning of crocodiles.

    Called goanna in Australia
    • ‘Probably the most famous species of monitor lizard is the Komodo Dragon which lives on several islands in Indonesia.’
    • ‘A good example is the savannah monitor, an African monitor lizard weighing about ten pounds, which spends most of its day patrolling its territory for tasty insects.’
    • ‘Beaded lizards and Gila monsters are opportunistic foragers, just as monitors are, eating any palatable thing they find.’
    • ‘I hurried over and he pointed out an enormous monitor lizard which had just crawled out of the water to sun itself on a rock.’
    • ‘Two million years ago bizarre creatures roamed the Australian continent - the flesh-eating giant rat-kangaroo, the thunder bird, the marsupial wolf, and a giant monitor lizard.’
  • 5historical A shallow-draught warship mounting one or two heavy guns for bombardment.

    • ‘They were up against John Dahlgren's naval force of monitors and warships.’


  • 1 Observe and check the progress or quality of (something) over a period of time; keep under systematic review.

    ‘equipment was installed to monitor air quality’
    • ‘To guard against corruption, those countries will use a system of peer review to monitor deployment of funds and progress toward good governance.’
    • ‘The polls were monitored by 125 observers from 33 countries.’
    • ‘Workplace exposure levels have been monitored on a regular basis, and the trend has been towards a decrease.’
    • ‘They will be responsible for developing data systems to track and monitor performance of general practitioners and ensure that the quality framework functions.’
    • ‘That council officers carry out a detailed review of boarded-up shops and devise a system for monitoring them.’
    • ‘The quality of hospital food is constantly monitored and menus are reviewed on a regular basis.’
    • ‘It will monitor the service and review performance at the end of the second year.’
    • ‘A lot of national and international observers are monitoring this election closely.’
    • ‘It has now become part of the network of Bird Observatories, which monitor bird migration around Britain and Ireland.’
    • ‘With concerns growing, election officials across the UK have agreed to allow election observers from abroad to monitor the campaign.’
    • ‘Their health is also monitored through periodic check ups and supplements.’
    • ‘The duration of light and intense exercise training was also monitored during this study period.’
    • ‘To monitor your systematic progress, record each day's results.’
    • ‘The system monitors all workflows in progress and interprets the results upon completion of each step.’
    • ‘The Government sees the Standard Assessment Tests as crucial to monitoring the progress of pupils and schools.’
    • ‘Room temperature and humidity need to be monitored and maintained within the recommended range.’
    • ‘Impacted wisdom teeth that are not causing problems should be monitored during regular visits to your dentist.’
    • ‘The patient is then monitored over a period of days while a video of the patient allows doctors to choose the best course of treatment.’
    • ‘Patients in the latest test will be monitored for two years.’
    • ‘The condition of the fiber was tracked by monitoring the holding current throughout an experiment.’
    observe, watch, keep an eye on, keep track of, track, keep under observation, keep watch on, keep under surveillance, surveil, check, keep a check on, scan, examine, study, record, note, oversee, supervise, superintend
    keep tabs on, keep a tab on, keep a beady eye on
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    1. 1.1Maintain regular surveillance over.
      ‘he was a man of routine and it was easy for an enemy to monitor his movements’
      • ‘May the government use electronic surveillance to monitor the movements and information use of suspected terrorists?’
      • ‘In the adjacent corner, a small, elevated closed-circuit camera monitored their every move.’
      • ‘He added that some local people were keeping the plant under surveillance and monitoring movements in and out of the plant.’
      • ‘The £10,000 contribution will cover half of the cost of a new CCTV camera to monitor the Twickenham Riverside area.’
      • ‘The cops were of course present, along with undercover men in the crowd and surveillance equipment monitoring our every move.’
      • ‘Eighteen surveillance cameras monitor the house and are observed continuously by a director or producer nearby.’
      • ‘He insists that Jani was kept in a sealed-off room under constant video surveillance and closely monitored.’
      • ‘The councillor has successfully lobbied for £25,000 for cameras to monitor the Eldene Centre, another area targeted by vandals.’
      • ‘The door is electronically locked and monitored by both surveillance cameras and employees.’
      • ‘Thousands of police, army troops and security men stood on guard in and around the Grand Mosque as surveillance cameras monitored the crowds.’
      • ‘For example, a video camera continuously monitors everything that transpires, whereas surveillance by wiretap will only be triggered when someone speaks.’
      • ‘The academy monitored her every action on her laptop and her user name would always reveal exactly who she was.’
      • ‘The diagram he drew of the surveillance equipment that monitored him was excellent.’
      • ‘Architectural elements control pedestrian access, and surveillance cameras monitor people as they approach the area.’
      • ‘For our own security, advanced surveillance aircraft can monitor the movement of bypassed enemy army units.’
      • ‘For 15 years the company used hidden cameras to monitor its 3,000 employees at its Granite City, Illinois steel mill.’
      • ‘This place had to be monitored by security cameras, he told himself, but he hadn't the time to be concerned about it.’
      • ‘A further bid for European funding, which would enable the area to be monitored by CCTV cameras, is also being considered.’
      • ‘The officer recalled a surveillance operation when detectives monitored them in a house in the Carndonagh area.’
      • ‘The cars, which will be monitored by police and cameras, will be parked in locations around Burnley and left with property on show in a bid to attract thieves.’
      vigil, guard, watch, monitoring, policing, beat, beat-pounding, patrolling, round, sentry duty
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    2. 1.2Listen to and report on (a foreign radio broadcast or a telephone conversation)
      ‘listening devices were used to monitor conversations’
      ‘it was not easy to discover exactly how many calls were monitored’
      • ‘What you're about to here is a conversation that my government monitored.’
      • ‘Word on the street has it that email, internet access, and telephone calls are being monitored closely.’
      • ‘The Europol document says the use of telephones - land lines and mobiles - will be monitored.’
      • ‘Telephonic communications of the German Army had been monitored and reported to the Allies by the French Resistance.’
      • ‘Their conversations were recorded and in many cases monitored in real time.’
      • ‘The threat of a reprisal strike was broadcast by the country's state-run radio, and monitored in Beijing.’
      • ‘Their communications - via telephone, email, fax - are monitored and disrupted.’
      • ‘He was monitoring the mob's wiretapped conversations through contacts he had in government.’
      • ‘There were no further details in the KCNA report, monitored in Beijing.’
      • ‘The report, monitored by the wire service, could not immediately be confirmed.’
      • ‘During this time, my home telephone was being monitored.’
      • ‘Telephone conversations would be monitored during the gag period, it said.’
      • ‘Then, suddenly remembering that their conversation was being monitored, he turned a bit red.’
      • ‘Corporate spies could also use an inexpensive scanner radio to monitor the conversation.’
      • ‘Each wiretap request must specify a particular telephone number or location to be monitored.’
      • ‘The report from Pyongyang was monitored in Tokyo by Kyodo News.’
      • ‘The act also stipulates that it must not be possible for a person to detect that his or her conversation is being monitored by the respective government agency.’
      • ‘One of the recon teams had a radio intercept operator monitoring enemy transmissions as the battle went on.’
      • ‘Some employers will monitor telephone conversations.’
      • ‘In March 1944, he became a liaison to the Australian Government to monitor and evaluate Japanese broadcasts.’
      listen in, spy, intrude
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    3. 1.3Check or regulate the technical quality of (a radio transmission or television signal)
      ‘a sound assistant monitors the signal on headphones’
      • ‘Sennheiser HD600 headphones were used to monitor the DV40 while on location.’
      • ‘The sound team sit in the same truck as the director, monitoring the presenter's and guest's sound levels’
      • ‘Anania says integration was important in metro area networking because transmissions need to be monitored at each node.’
      • ‘To specifically monitor the fluorescence signal, we placed a bandpass filter centered at 580 nm in front of the optical detector.’
      • ‘The negative peak was observed only if the PA signal had been monitored at low, and not high, frequencies.’


Early 16th century (in monitor): from Latin, from monit- warned, from the verb monere. monitor dates from the 1930s.