TIL "tortoises are not turtles" is actually according to British English, whereas in US English, tortoises are a type of turtle and sea-turtles have to be called sea-turtles if you don't want to include tortoises and terrapins.
Also Australia has land-turtles (British), so I guess those are land-sea-turtles?
en.wikipedia.org/wiki/Turtle
en.wikipedia.org/wiki/Turtle
order of reptiles characterized by a shell https://en.m.wikipedia.org/wiki/Turtle