adjective. Definition of à deux (Entry 2 of 2) : involving two people especially in private a cozy evening à deux Deux and D'eux means "of them" or "about them" while also being the number "two" in French.
noun. a portion or division of a whole that is separate or distinct; piece, fragment, fraction, or section; constituent: the rear part of the house;to glue the two parts together. an essential or integral attribute or quality: a sense of humor is part of a healthy personality. a section or division of a literary work.