(logic) The property (of an argument) of not only being valid, but also of having true premises.
(logic) The property of a logical theory that whenever a wff is a theorem then it must also be valid. Symbolically, letting T represent a theory within logic L, this can be represented as the property that whenever
(geography) A long narrow inlet, or a strait between the mainland and an island; also, a strait connecting two seas, or connecting a sea or lake with the ocean.