from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A thick-walled structure in which sporozoan zygotes develop and that serves to transfer them to new hosts.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A thick-walled structure under a mosquito's outer gut lining, formed by an ookinete.
oo- + cyst (Wiktionary)