I think I'll just go ahead and clear it up with the science jabber seeing as it's not going to get much more complicated, lol. *getting book*
Okay of the shelled reptiles you have several groups under the order Testudines
The quick answer is that when ...blah blah blah my long hard to understand answer I just spent an hour writing is going to be cut so I can paste in this nice easy answer I found on a webpage, lol
"In common usage in the United States, the word turtle is an inclusive word that refers to all species of water turtle, sea turtle, box turtle, terrapin and tortoise. The word tortoise refers to a particular type of turtle that is well adapted to life on land.
Scientists group all turtles together in the "order" known as TESTUDINES. This order includes about a dozen living "families" of turtle. Tortoises are a specialized clade or subgroup of the order TESTUDINES that are known as the Testudinidae.
According to Dr. Kristin Berry, the following distinction is made between the terms turtle and tortoise in the US:
A tortoise is a land dwelling turtle with high domed shell and columnar, elephant-shaped hind legs. Tortoises go to water only to drink or bathe.
In contrast, the word turtle is used for other turtles: pond turtles, river turtles, box turtles, musk turtles, sea turtles, etc.
So, tortoises form a subgroup that can be distinguished from other groups of turtle but they are "turtles" nonetheless."
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