(1):

(a.) Asserting only a part of what is asserted in a related proposition.

(2):

(a.) Ranked or ranged below; subordinate; inferior; specifically (Mil.), ranking as a junior officer; being below the rank of captain; as, a subaltern officer.

(3):

(n.) A person holding a subordinate position; specifically, a commissioned military officer below the rank of captain.

(4):

(n.) A subaltern proposition.