Circumference is for the distance around a circle. Perimeter is the distance around a flat figure that is a non-circle.

“Circumference” is from Latin and “perimeter” is from Greek. We probably don’t need both, but we inherited both.

think back to the ancients and earlier. you have to measure them differently on objects, and reproduce them differently. the people who first built these ideas had to be precise about something their parents’ generations hadn’t done before.

Just wait for squarcumference and rhombcumference

And you're a chemistry teacher? Wow

A little etymology. Latin circum = around (as around a circle); ferre = to carry or bear. Together, then, carry or bear around (a circle). Greek peri = around (not necessarily as around a circle; so perimortem is around time of death, for instance); meter = measure. Together, then, measure around something, whether circular or not. In math the difference is important since for circumference you must use π but not for perimeters.

I may be completely wrong here, but I think circumference is a measurement, whereas perimeter is a boundary. True?

One is Latin, the other is Greek. That’s pretty much it

There are plenty of words relating to circles specifically. Radian, angular displacement/velocity/acceleration, torque could go in this category, diameter. It’s simply to differentiate linear and angular/circular values.

Perimeter isn’t always the same in a 3D shape, and we use its dimensions and volume to determine how much space it takes up. Circumference is the same on a sphere or circle no matter what cross-section you take.