Definition of terrapins:
(n) :
(countable) Any of several small turtles of the families Emydidae and Geoemydidae found throughout the world.
(n) :
(countable, obsolete) Any of several small turtles native to North America that live in brackish or fresh water, especially the diamondback terrapin (Malaclemys terrapin).
(n) :
(countable, obsolete) Any turtle.
(n) :
(uncountable, obsolete) The flesh of such a turtle used as food.