Definition of cyst in English:



  • 1In an animal or plant, a thin-walled, hollow organ or cavity containing a liquid secretion; a sac, vesicle, or bladder.

    • ‘The epithelial cells lining the cyst contained abundant mucin vacuoles that filled the cytoplasm of the luminal half of the cells.’
    • ‘In the lumen of the cysts, eosinophilic or blue secretions were frequently seen, with sometimes targetoid secretion.’
    1. 1.1Medicine In the body, a membranous sac or cavity of abnormal character containing fluid.
      • ‘Sometimes a thin needle is used to puncture the cyst and take out fluid to test for the Echinococcus infection.’
      • ‘Complications include rupture of the cyst into the peritoneal cavity, which results in urticaria, anaphylactic shock, eosinophilia, and implantation into the omentum and other viscera.’
      • ‘Biopsy specimens of those cysts and the liver cyst revealed benign mesothelial cysts and focal papillary mesothelioma.’
      • ‘The walls of the cysts were mostly membranous with variable thickness.’
      • ‘In rare cases, ovarian cysts can cause abnormal amounts of hormones to be produced.’
      • ‘In a molar pregnancy, the early placenta grows abnormally into a mass of cysts.’
      • ‘We removed an aspergilloma located in the right lower lobe of the lung in a 48-year-old woman with a bronchial cyst and rheumatoid arthritis.’
      • ‘At least a third of women with multiple miscarriages appear to have polycystic ovary syndrome, which is characterized by hormonal abnormalities and multiple cysts on the ovaries.’
      • ‘These pimples vary according to the severity of the acne and range from whiteheads, blackheads, pustules, nodules to cysts.’
      • ‘Using tiny surgical tools attached to the laparoscope, the surgeon can make a small cut in the cyst to drain the fluid away.’
      growth, abscess, boil, blister, bleb, wen, carbuncle
      vesicle, vesication, hydatid, oocyst, saccule, steatoma
      View synonyms
    2. 1.2A tough protective capsule enclosing the larva of a parasitic worm or the resting stage of an organism.
      • ‘The eggs mature to neotenous larvae inside the walls of the cyst.’
      • ‘The cysts contain tapeworm larvae that develop into adult worms in people who eat under-cooked or raw meat from an infested pig.’
      • ‘One gram of fecal matter can contain 10 million viruses, one million bacteria, 1,000 parasite cysts, and 100 worm eggs.’
      • ‘Resting cysts represent a dormant stage in which normal life processes are greatly reduced.’
      • ‘Vigorous boiling for one minute kills bacteria, including disease-causing organisms and giardia cysts.’
      • ‘Giardia organisms form a resistant cyst that is shed by the host in its waste.’
      • ‘Potato cyst eelworms are normally hatched from their protective cyst in spring.’
      • ‘Some filters can remove even small organisms like cysts and bacteria and small particles like asbestos fibers.’
      • ‘The internal structure of the organism contained within the cyst can be easily appreciated.’
      • ‘At least three minutes of boiling is necessary but 20 minutes of boiling will make water safe and pure from all the harmful bacteria viruses, worms and cysts of amoeba.’


Early 18th century: from late Latin cystis, from Greek kustis bladder.