Enter the lists? (5)

I believe the answer is:
enrol
'enter' is the definition.
(I know that enrol is a type of register)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for enrol that I've seen before include "register for classes" , "Sign on, register" , "Register officially" , "Register (as member)" , "Sign up (member)" .)