ADD

noun

1. An act or instance of adding.
2. An additional enemy that joins a fight after the primary target.

verb

1. 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.
2. To sum up; to put together mentally.
3. To combine elements of (something) into one quantity.