The part of the scallop that is most often eaten is the adductor muscle that opens and closes the shell.
Scallops have two shells and you can also eat the reproductive organs, or roe which are all edible but not everyone eats those parts.
Most people just eat those adductor muscles that allow the shell to open and close and then throw the rest away.
But if you prefer to eat the rest of the scallop you certainly can.
Scallops also are bivalve mollusks which means the scallops have two shells.
A scallop is any one of numerous species of saltwater clams or marine bivalve mollusks in the taxonomic family Pectinidae, the scallops.