/kad"is werrm'/ , n.
the aquatic larva of a caddisfly, having an armored head and a pair of abdominal hooks, and typically living in a case built from sand or plant debris. Also called caddis, caddice, strawworm .
[ 1615-25; caddis (perh. pl., taken as sing., of caddy, dim. of cad larva, ghost) + WORM ]