Definition of cyst in English:



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

    • ‘In the lumen of the cysts, eosinophilic or blue secretions were frequently seen, with sometimes targetoid secretion.’
    • ‘The epithelial cells lining the cyst contained abundant mucin vacuoles that filled the cytoplasm of the luminal half of the cells.’
  • 2Medicine
    A membranous sac or cavity of abnormal character in the body, containing fluid.

    • ‘The walls of the cysts were mostly membranous with variable thickness.’
    • ‘In a molar pregnancy, the early placenta grows abnormally into a mass of cysts.’
    • ‘Biopsy specimens of those cysts and the liver cyst revealed benign mesothelial cysts and focal papillary mesothelioma.’
    • ‘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.’
    • ‘Sometimes a thin needle is used to puncture the cyst and take out fluid to test for the Echinococcus infection.’
    • ‘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.’
    • ‘In rare cases, ovarian cysts can cause abnormal amounts of hormones to be produced.’
    • ‘Using tiny surgical tools attached to the laparoscope, the surgeon can make a small cut in the cyst to drain the fluid away.’
    • ‘These pimples vary according to the severity of the acne and range from whiteheads, blackheads, pustules, nodules to cysts.’
    • ‘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.’
    growth, abscess, boil, blister, bleb, wen, carbuncle
    View synonyms
  • 3Zoology
    A tough protective capsule enclosing the larva of a parasitic worm or the resting stage of an organism.

    • ‘Giardia organisms form a resistant cyst that is shed by the host in its waste.’
    • ‘The eggs mature to neotenous larvae inside the walls of the cyst.’
    • ‘Potato cyst eelworms are normally hatched from their protective cyst in spring.’
    • ‘The cysts contain tapeworm larvae that develop into adult worms in people who eat under-cooked or raw meat from an infested pig.’
    • ‘Vigorous boiling for one minute kills bacteria, including disease-causing organisms and giardia cysts.’
    • ‘The internal structure of the organism contained within the cyst can be easily appreciated.’
    • ‘Some filters can remove even small organisms like cysts and bacteria and small particles like asbestos fibers.’
    • ‘Resting cysts represent a dormant stage in which normal life processes are greatly reduced.’
    • ‘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.’
    • ‘One gram of fecal matter can contain 10 million viruses, one million bacteria, 1,000 parasite cysts, and 100 worm eggs.’


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