Source : Webster's Revised Unabridged Dictionary (1913)

Amphipod \Am"phi*pod\, n. (Zo["o]l.)
   One of the Amphipoda.

Amphipod \Am"phi*pod\, Amphipodan \Am*phip"o*dan\, a. (Zo["o]l.)
   Of or pertaining to the Amphipoda.

Source : WordNet®

amphipod
     n : a kind of malacostracan crustacean