Definition from Wiktionary, the free dictionary
cyst (plural cysts)
- A pouch or sac without opening, usually membranous and containing morbid matter, which develops in one of the natural cavities or in the substance of an organ.
sac which develops in the natural cavities of an organ
From Proto-Germanic *kustuz (“choice, trial”), from Proto-Indo-European *ǵéwstus. Cognate with Old Saxon cust (Dutch kust), Old High German chust, Old Norse kostr (“choose, chance, opportunity, value”).
Declension of cyst (strong i-stem)