Question

what id the difference between a defined and an undefined term in geometry

Answer 1

One is defined and the other isn't.

Answer 2

I think wrong area not sure?

Answer 3

This has come up before... While "defined term" does not have a very technical definition in mathematics, I believe what you are referring to is a point, a plane, or a line.

These three concepts come up in geometry a lot. They have no physical structure and are simply ideas used to construct geometrical mathematics.