The term ASSUMPTION SUBJECT refers to a concept in logic and philosophy. The crossword solutions for this term are LEMMA (5 letters), POSTULATE (9 letters), and STMARY (6 letters). A lemma is a proposition that is assumed or taken for granted in order to prove another proposition. A POSTULATE is an assumption or axiom that is accepted without proof. A stmary is a statement that is assumed to be true and used as the basis for further reasoning. All three of these terms refer to assumptions that are made in order to prove a certain point.