(radio) The addition of a song to a station's playlist.

(computer science) An act or instance of adding.

(video games) An additional enemy that joins a fight after the primary target.

(transitive) To join or unite (e.g. one thing to another, or as several particulars) so as to increase the number, augment the quantity, or enlarge the magnitude, or so as to form into one aggregate.

To sum up; to put together mentally; to add up.

(transitive) To combine elements of (something) into one quantity.

(transitive) To give by way of increased possession (to someone); to bestow (on).

(transitive) To append (e.g. a statement); to say further information; to add on.

(intransitive) To make an addition; to augment; to increase; to add on.

(intransitive, mathematics) To perform the arithmetical operation of addition.

(intransitive, video games) To summon minions or reinforcements.