Amphipoda

plural noun

Am·​phip·​o·​da

amˈfipədə

: a large group, usually an order, of malacostracan crustaceans (division Peracarida) comprising the beach fleas and related forms; being mostly of small size with laterally compressed body, four anterior pairs of thoracic limbs directed forward, and three posterior pairs directed backward and upward, the thoracic limbs bearing gills; being usually aquatic in fresh or salt water, and a few (as the whale louse) being parasitic

Word History

Etymology

New Latin, from amphi- + -poda

First Known Use

1817, in the meaning defined above

Love words?

You must — there are over 200,000 words in our free online dictionary, but you are looking for one that’s only in the Merriam-Webster Unabridged Dictionary.

Start your free trial today and get unlimited access to America's largest dictionary, with:

• More than 250,000 words that aren't in our free dictionary
• Expanded definitions, etymologies, and usage notes
• Advanced search features
• Ad free!