Source : Webster's Revised Unabridged Dictionary (1913)

Quahog \Qua"hog\, Quahaug \Qua"haug\, n. [Abbrev. fr.
   Narragansett Indian poqua[^u]hock.] (Zo["o]l.)
   An American market clam ({Venus mercenaria}). It is sold in
   large quantities, and is highly valued as food. Called also
   {round clam}, and {hard clam}.

   Note: The name is also applied to other allied species, as
         {Venus Mortoni} of the Gulf of Mexico.