Malacostraca

plural noun

Mal·​a·​cos·​tra·​ca

ˌmaləˈkästrəkə

: a major subclass of Crustacea including most of the well-known marine, freshwater, and terrestrial members of the group (as lobsters, crabs, shrimps, sow bugs, beach fleas)

malacostracan

¦⸗⸗¦kästrəkən 

adjective or noun

malacostracous

-kəs

adjective

Word History

Etymology

New Latin, from Greek malakostraka, neuter plural of malakostrakos soft-shelled, from malak- malac- + -ostrakos (from ostrakon shell)

First Known Use

1819, in the meaning defined above

The Ultimate Dictionary Awaits

Expand your vocabulary and dive deeper into language with Merriam-Webster Unabridged.

1. Expanded definitions
2. Detailed etymologies
3. Advanced search tools
4. All ad-free

Discover what makes Merriam-Webster Unabridged the essential choice for true word lovers.

Start Your Free Trial Now