Change label variation

Greetings, I lame different types of sizes:

Shoe sizes, children’s sizes, trouser sizes, etc. As you can see in picture 1

I have differentiated them so that they can be applied to the product that requires that type of size.

How could I change the label shown on the ftontend, keeping a different one on the backend

Example:

Backend: Size Pants (to be able to differentiate when adding to the product)

Frontend: Size

See image 2

I hope I’ve made myself clear.