Noun
(zoology) Any amphipod of the suborder Gammaridea.
Synonym: gammaridean
(zoology, less common) Any amphipod of the family Gammaridae.
Source: en.wiktionary.orgThis modification of gammarid behavior by the acanthocephalan is thought to increase the rate of transmission of the parasite to its next host by increasing the susceptibility of the gammarid to predation. Source: Internet