amphipod

This term is primarily used in biological and ecological contexts. It describes a specific group of crustaceans known for their sideways-compressed bodies, which distinguishes them from the more common shrimp or krill. In scientific literature, it is used as a precise taxonomic identifier rather than a general description.

Because it refers to a biological organism, the word follows standard English countability rules for animals. It is used in the singular when referring to a single individual or the species in general, and in the plural when referring to multiple specimens or populations.