Definition of propellant in US English:



  • 1A substance that propels something.

    • ‘One of its four strap-on motors, powered by liquid propellants, did not build up enough thrust.’
    • ‘Liquid helium from a tank in the lunar module was used to assure a steady flow of propellants to the descent engine.’
    • ‘Argon is also an ideal carrier gas, a propellant with no propensity to react.’
    • ‘In the more popular system, the propellant is a liquefied gas.’
    • ‘All stages of these are made of solid propellants.’
    • ‘The first two stages used liquid fuel, the third stage solid propellant.’
    • ‘Similarly, it would be too expensive to give each launched satellite enough propellant to deorbit itself at the end of its service life.’
    • ‘Booster systems rerouted propellants to the seven other engines.’
    • ‘The propellant comes together in an eight-foot combustion chamber, where the liquid oxidizer is converted into a gas, then ignited to start the engine.’
    • ‘Such a maneuver would require a significant amount of propellant for conventional rocket systems.’
    • ‘The long-planned impact is necessary now that the onboard propellant is nearly depleted.’
    • ‘It will take too much propellant to be an efficient mission.’
    • ‘With the improvement in propellant in the second stage came an increase of thrust plume temperature.’
    • ‘Manufacturing propellant from the atmosphere of Mars also could reduce the mass of propellant that must be hauled to Mars.’
    • ‘These inhalers use a chemical propellant to push the medication out of the inhaler.’
    • ‘Only 59 kilograms of xenon propellant were used.’
    • ‘A fixed amount of propellant is contained in the rocket motor.’
    • ‘Fourthly, the room used to fill the satellites with propellant has ducts around the outside.’
    • ‘In deep space, the propellant can be small amounts of ionized xenon gas, accelerated to enormous speeds within a new kind of engine.’
    • ‘Instead, the focus was to be on loads featuring some of the newer propellants.’
    1. 1.1 An inert fluid, liquefied under pressure, in which the active contents of an aerosol are dispersed.
      • ‘He explained that deodorants and other aerosols contain propellants, like butane, to dry the particles.’
      • ‘These metal cans are capped with valves that seal the pressurized propellant in the can and control dispensing of the contents.’
      • ‘The other thing our government needed to protect us from was the stuff used as propellant in aerosol cans.’
      • ‘They have uses as propellants in aerosol spray cans, refrigerant gases, and foaming agents for blown plastics.’
      • ‘They include ether, chloroform and halothane; the ones that commonly cause addiction are ethyl alcohol, propellants in spray cans and petrol.’
      • ‘In automobiles, for example, the thermal decomposition of sodium azide produces a large amount of nitrogen gas that acts as a propellant that causes air bags to open on impact.’
      • ‘By the mid-1970s, the United States government banned the use of CFCs as aerosol propellants but it resisted a total ban for all industries.’
      • ‘Aerosol propellants contain flammable and nerve-damaging ingredients as well as tiny particles that can lodge in your lungs.’
      • ‘CFCs had been used commercially as refrigerants since the 1930s, but because they were inert and non-poisonous they were soon used for many other applications, most notably as propellants in aerosol spray cans.’
      • ‘For example, chlorofluorocarbons have been used in the second half of the 20th century as nonflammable refrigerants, industrial solvents, foaming agents, and aerosol propellants.’
      • ‘Today, almost all aerosol cans contain alternative propellants, such as liquefied petroleum gas, which do not pose as serious a threat to the environment.’
      • ‘Chlorofluorocarbons were developed and used as refrigerants, blowing agents for polyurethane foam, and propellants in spray cans.’
      • ‘These substances, also known as freons, were once used extensively as coolant fluids in refrigerators and air conditioners, and as propellants in aerosol cans.’
      • ‘This gas has long been used as a propellant in aerosol sprays and in refrigerators.’
      • ‘In the 1970s, the United States, along with several other countries, banned the use of CFCs as aerosol propellants.’
      • ‘Carbon dioxide is used to make carbonated beverages, in fire extinguishers, and as a propellant in aerosol products.’
      • ‘Alternatively, the aerosol container may be inverted allowing direct access to the propellant via the dip tube.’
      • ‘These inhalers don't use a chemical propellant to push the medication out of the inhaler.’
      • ‘The data on whether the majority of cancers, neurological problems, and other health problems are associated with exposure to fuels, propellants, or combustion products were inadequate to draw conclusions.’
    2. 1.2 An explosive that fires bullets from a firearm.
      • ‘Of course, the scanner could only detect metals, energy sources and chemical compounds that could be combined into propellants and explosives.’
      • ‘Liquid propellants clearly have the edge over gunpowder for military applications such as this.’
      • ‘The finding would be consistent with the plant's stated production capabilities in the field of basic raw materials for explosives and propellants.’
      • ‘The parent companies are aiming to create a leading propellants and explosives company in Europe, drawing on advanced technologies and in-depth knowledge of this business.’
      • ‘Black powder loading, though simple, requires different techniques than those used with smokeless propellants.’
      • ‘To fire the weapon a projectile containing the propellant and explosive is dropped into the muzzle.’
      • ‘The rapid expansion of gases caused by the burning propellant propels the projectile from the tube toward the target.’
      • ‘Smokeless propellants are expensive and not often used in making fireworks.’
      • ‘And we'll be doing some testing, including small-scale weapons testing, just to see how these propellants react in a gun environment.’
      • ‘However, the use of this explosive mixture of saltpetre, charcoal, and sulphur as a propellant for bullets from firearms, and thus gun powder, is a western development and one which took place gradually from the 13th century.’
      • ‘Many of the wars in this century were fought with TNT as the main explosive and with gunpowder as the main propellant of bullets and artillery shells.’
      • ‘By definition, explosive ordnance is any munitions, weapon delivery system, or ordnance item that contains explosives, propellants, and chemical agents.’
      • ‘It is necessary that all Field Artillery officers understand the different types of propellants, projectiles, fuzes, and their proper use, so that we can supervise our subordinates.’
      • ‘Pyrotechnics came to Europe in the thirteenth century, where they quickly revolutionized warfare with their use as propellants in cannons and rockets, and in 1677, miners applied the science to blasting rock for the first time.’
      • ‘In low explosives, such as the propellant in a bullet cartridge, the reaction occurs relatively slowly and the pressure isn't as damaging.’
      • ‘When the firing pin strikes the primer, it ignites the propellant.’
      • ‘The rapidly expanding gases from the burning propellant force the projectile through the cannon tube.’
      • ‘Many centuries ago the Chinese first employed crude rockets using solidified propellants to scare their enemies with the resulting loud noises and flashing overhead lights.’
      • ‘When smokeless propellants were safely ensconced in society, what did they do with the .45 Colt?’
    3. 1.3 A substance used as a reagent in a rocket engine to provide thrust.
      ‘rocket propellants’
      • ‘A fixed amount of propellant is contained in the rocket motor.’
      • ‘The first rockets used solid propellants, such as black powder, but they were very inefficient.’
      • ‘The end result is a total of 108 tonnes of methane/oxygen rocket propellant.’
      • ‘My husband was a research chemist working on propellants - a real rocket scientist.’
      • ‘Perchlorate is the primary ingredient of solid rocket propellant that is increasingly found in soil and water.’
      • ‘Most launch vehicles use liquid propellants, but some use motors with solid fuels.’
      • ‘The extra propellant provides an additional 50 tonnes of thrust in the first 20 seconds following liftoff.’
      • ‘The maneuver is necessary, since onboard propellant is nearly depleted.’
      • ‘Rocket propellants come in two parts, fuel and oxidizer, which work together to keep an engine burning.’
      • ‘The long-planned impact is necessary now that the onboard propellant is nearly depleted.’
      • ‘More like rocket engines, jets produce thrust by burning propellant (jet fuel mixed with air) and forcing the rapidly expanding gases rearward.’
      • ‘They therefore deliver about ten times as much thrust per kilogram of propellant used, making them very ‘fuel-efficient’.’
      • ‘Perchlorate is a waterborne contaminant left over from propellants and rocket fuels.’
      • ‘The exhaust from an ion engine travels up to 10 times faster than does the exhaust from a chemical engine, generating far more thrust per pound of propellant.’
      • ‘He also theorized that liquid propellant made for a far more powerful and efficient fuel for rockets than solid propellant.’
      • ‘Slower burning powders tend to deliver better accuracy than faster burning propellants, even when velocities are identical.’
      • ‘To get to the Moon she expended only about 60 kilograms of xenon propellant.’
      • ‘Most NASA spacecraft rely on some form of chemical propellant to push themselves through space.’
      • ‘A pedant or two might ask if you really mean rocket propellants when you say rocket fuel.’
      • ‘When the propellants combine within the engine, they produce thrust.’
      power source, heat source, combustible
      View synonyms


  • Capable of propelling something.

    ‘propellant gases’
    • ‘A wider gap allows more of the propellant gases to escape out to the side.’
    • ‘Once extracted, these resources could be used for life support, propellant production, and construction and shielding.’
    • ‘The cases are cleaned, inspected and reassembled for propellant casting, and a new nozzle and igniter are installed.’
    • ‘Aerosol sprays contain one or more pesticides in a solvent and a propellant gas.’
    • ‘Just about everything should be easily removable except the main propellant tanks.’
    • ‘The mishap took place in the Center's solid propellant space booster plant, where rocket motors are filled with the solid fuel required for their operation.’
    • ‘The two-stage missile is equipped with solid propellant booster and sustainer rocket motors.’
    • ‘Loose tie straps or wrappings have the effect of increasing the diameter of the propellant charge.’
    • ‘The solid propellant motor has a short burn time and very low smoke emission.’
    • ‘If this happens through a critical component, such as the flight computer or propellant tank, this could be fatal.’
    • ‘Trident II is a three-stage solid propellant missile with supersonic speed.’
    • ‘The missile consists of a two-stage solid propellant rocket motor, a separation system and three high density darts.’
    • ‘Again, these factors are very important to soldiers who want to present the smallest possible opportunity for the enemy to locate them based on muzzle flash and propellant smoke.’
    • ‘Once again, the speaker took a moment to state that he felt this method would eventually become feasible, once the problems of hyperbolic re-entry and high-energy propellant use in return stages were faced.’
    • ‘They do not require propellant loading on the launch pad, and they can be stored for long periods.’
    • ‘The other main weakness is the lack of armor around the propellant storage tanks.’
    • ‘The high-pressure propellant gas drives the liquid product up the plastic tube and out through the nozzle.’
    • ‘After leaving the launcher the solid propellant rocket motor accelerates the missile to supersonic speed.’
    • ‘The probability of a motor failure, along with propellant leaks, etc., for a multiengine cluster is greater than for a single motor of similar reliability.’


Mid 17th century: originally from Latin propellent- ‘driving ahead (of oneself)’, from the verb propellere, later from propel.