A common name, in distinction from a proper name. A
   common name, or appellative, stands for a whole class, genus, or
   species of beings, or for universal ideas. Thus, tree is the name of
   all plants of a particular class; plant and vegetable are names of
   things that grow out of the earth. A proper name, on the other hand,
   stands for a single thing; as, Rome, Washington, Lake Erie.