universal (Noun) — (linguistics) a grammatical rule (or other linguistic feature) that is found in all languages.
universal (Noun) — (logic) a proposition that asserts something of all members of a class.
universal (Noun) — A behavioral convention or pattern characteristic of all members of a particular culture or of all human beings. ex. "some form of religion seems to be a human universal"
universal (Noun) — Coupling that connects two rotating shafts allowing freedom of movement in all directions. ex. "in motor vehicles a universal joint allows the driveshaft to move up and down as the vehicle passes over bumps"
universal (Adjective) — Of worldwide scope or applicability. ex. "universal experience"
universal (Adjective) — Applicable to or common to all members of a group or set. ex. "the play opened to universal acclaim" ex. "rap enjoys universal appeal among teenage boys"
universal (Adjective) — Adapted to various purposes, sizes, forms, operations. ex. "universal wrench" ex. "universal chuck" ex. "universal screwdriver"