/mal'euh kos"treuh keuhn/ , adj.
1. belonging or pertaining to the crustacean subclass Malacostraca, which includes the lobsters, shrimps, crabs, etc.
n.
2. a malacostracan crustacean.
[ 1825-35; Malacostrac ( a ) order of crustacea ( malak- MALACO- + -ostrakos, adj. deriv. of óstrakon shell (of mollusks, etc.); cf. OSTRACIZE) + -AN ]