1) Genus mercenaria 2) Mollusk genus 
Mercenaria is a genus of edible saltwater clams, marine bivalve molluscs in the family Veneridae, the Venus clams. The genus Mercenaria includes the quahogs, Mercenaria mercenaria, the northern quahog or hard clam, and M. campechiensis, the southern quahog. These two species commonly hybridise where their ranges overlap. Mercenaria mercenaria is f...
• (n.) The quahog.
Mer`ce·na'ri·a noun [ New Latin See Mercenary .] (Zoology) The quahog. 
[n] - a genus of Veneridae
genus Mercenaria noun a genus of Veneridae