noun The act of uniting or joining two or more things into one.
noun The state of being united or joined; a state of unity or harmony.
noun Something united, or made one; something formed by a combination or coalition of parts or members; a confederation; a consolidated body; a league.
noun A trade union; a workers' union.
noun An association of students at a university for social and/or political purposes; also in some cases a debating body.
noun A joint or other connection uniting parts of machinery, such as pipes.
noun The set containing all of the elements of two or more sets.