a cyst containing watery fluid and the larvae of certain tapeworms (esp. genus Echinococcus), found in the body tissue, esp. the liver, of many animals
adjective
of or like such a cyst
See hydatid in American Heritage Dictionary 4
(hīˈdə-tĭd)
noun
A cyst formed as a result of infestation by larvae of the tapeworm Echinococcus granulosus.