Contention, proposition (6)
I believe the answer is:
thesis
I believe this is a double definition.
'contention' is the first definition.
(thesaurus)
'proposition' is the second definition.
(I know that thesis is a type of assumption)
(Other definitions for thesis that I've seen before include "student's work" , "Proposition" , "Treatise advancing a new point of view resulting from research" , "Student dissertation" , "Scholarly dissertation" .)