Grammar .

any member of a small class of words distinguished in many languages by their function as connectors between words, phrases, clauses, or sentences, as and, because, but, however.

any other word or expression of similar function, as in any case.

the act of conjoining; combination.

the state of being conjoined; union; association

The police, in conjunction with the army, established order.

a combination of events or circumstances.

Logic .

a compound proposition that is true if and only if all of its component propositions are true.

the relation among the components of such a proposition, usually expressed by AND or & or .

Astronomy .

the coincidence of two or more heavenly bodies at the same celestial longitude.

the state of two or more such coinciding heavenly bodies.

Astrology . the coincidence of two or more heavenly bodies at the same celestial longitude, characterized by a unification of the planetary energies; an astrological aspect.

adjective

combinative , combinatorial , conjugational , conjugative , connectional , connective