Yo might mention the brand/model/year (or some of that) to help better determine what you actually mean.
The pedal is what you put your foot on and screws to the crank/arm.
The crank/arm "Big End" attaches to the Bottom Bracket (BB). Method of attachment differs. THAT'S very important to know.
1 piece crank or ??

This may help identify what you have-
https://www.parktool.com/en-us/blog/...&area%5B%5D=51