Terrapin and Turtle

Terrapin noun - Any of various edible North American web-footed turtles living in fresh or brackish water.

Turtle and terrapin are semantically related In some cases you can use "Turtle" instead a noun "Terrapin".

Turtle noun - Any of various aquatic and land reptiles having a bony shell and flipper-like limbs for swimming.

Terrapin and turtle are semantically related in reptile topic. You can use "Terrapin" instead a noun "Turtle".