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