caddisworm

noun

cad·​dis·​worm ˈka-dəs-ˌwərm 

: the larva of a caddis fly that lives in and carries around a silken case covered with bits of debris

Illustration of caddisworm

Word History

Etymology

probably alteration of obsolete codworm; from the case or tube in which it lives

First Known Use

1622, in the meaning defined above