Terrapins, tortises, turtles

Question
What is the difference between the three? Terrapins, tortises and turtles?

Answer
In America:
- Turtle is the generic name, as well as the name of species that live at least partly in water.
- Tortoise are land dwellers, especially those in the Family Testudinidae (turtles with elephant-like front legs).
- Terrapins are either turtles we can eat (which is actually all of them) in a largely Southern usage, or the Diamondback terrapin from the salt marshes of the southeast.

In Europe:
- Turtle are fully aquatic- the sea turtles and turtles that rarely leave the water.
- Tortoise are the land turtles, like in America.
- Terrapins are semi-aquatic turtes, what we call 'pond turtles'.

The oddest one is the Box turtle-
- Turtle is part of the name.
- Tortoise is the lifestyle.
- Terrapin is the genus (Terrapena)