1.NounA dollar coin, whether made from silver or not.
"In Las Vegas, many of the slot machines use silver dollars."
2.NounA small pancake.
"Alice went to the diner and ordered a stack of silver dollars with butter and blueberry syrup."
3.NounSeveral species of tropical freshwater fish of the genus Metynnis, of the family Characidae or Serrasalmidae, of which Metynnis argenteus is one; popular for aquariums; so named from their shape and flashing silver color.