Students take First Lady to be equal (5)
I believe the answer is:
level
'be equal' is the definition.
(thesaurus)
'students take first lady' is the wordplay.
'students' becomes 'll'.
'take' means one lot of letters goes inside another.
'first lady' becomes 'eve' (I've seen this before**).
'll' enclosing 'eve' is 'LEVEL'.
'to' is the link.
(Other definitions for level that I've seen before include "Palindromic tier?" , "Storey - stage" , "Regular" , "Horizontal plane - a palindrome" , "Flush" .)