Is It: Oar ~ a rowing tool; or
. Or ~ a conjunction (a part of speech); or
. Ore ~ metal bearing rock;
Is It: Opposite ~ reverse of; or
. Apposite ~ appropriate;
Is It: Oral ~ of the mouth; or
. Aural ~ of the ear;
Is It: Ordinance ~ a command; or
. Ordnance ~ military equipment;
Is It: Ought ~should; or
. Aught ~ anything; or
. ~ zero;