in biology, "sac or pouch serving as a receptacle for eggs," 1875; see oo- "egg" + cyst.
Entries linking to oocyst
oo-
word-forming element meaning "egg, eggs," from Greek ōon "egg," cognate with Latin ovum, Old Norse egg,from PIE *ōwyo‑, *ōyyo‑ "egg," which perhaps is a derivative of the root *awi- "bird."
cyst n.
"bladder-like bag or vesicle in an animal body," 1713, from Modern Latin cystis (in English as a Latin word from 1540s), from Greek kystis "bladder, pouch," which is of uncertain etymology.