Quahog, or hard clam, is a species of edible clam found on the Atlantic coast of North America. The term is unique to the coast of Massachusetts and Rhode Island; elsewhere the same species is simply called "clam". In the Cape Code region, small quahogs are called "countneck" or "littleneck", while slightly larger ones are called "topstone" or "cherrystone."
Note that Pacific littleneck clams are a different species and are more similar to Manila clam.
Name origin
Quahog is derived from an Algonquin language, probably Narragansett, poquaûhock, or Pequot p'quaghhaug.
How to serve
Littlestone clams are usually served steamed, with a light sauce or as clams casino, or raw on the half-shell.
Cherrystone clams are larger enough to grill, stuff and broil, or use in a sauce. They are also prepared raw on the half-shell.
The largest quahogs, sometimes called "chowder clams", are, not surprisingly, best used in chowders. They are best used in gently simmered soups after a coarse chop.