Formula; hypothesis (7)
I believe the answer is:
theorem
I believe this clue is a double definition.
'formula' is the first definition.
(I've seen this before)
'hypothesis' is the second definition.
(I've seen this before)
(Other definitions for theorem that I've seen before include "mathematical achievement" , "Proof" , "Mathematical formula" , "Demonstrable proposition" , "Proven proposition" .)