add (Verb) — Make an addition (to); join or combine or unite with others; increase the quality, quantity, size or scope of. ex. "We added two students to that dorm room" ex. "She added a personal note to her letter" ex. "Add insult to injury" ex. "Add some extra plates to the dinner table"
add (Verb) — State or say further. ex. "'It doesn't matter,' he added"
add (Verb) — Provide a particular quality or character. ex. "The music added a lot to the play" ex. "This adds a light note to the program"
add (Verb) — (arithmetic) make an addition by combining numbers. ex. "Add 27 and 49, please!" ex. "add together 27 and 49, please!"
add (Verb) — Determine the sum of. ex. "Add all the people in this town to those of the neighbouring town" ex. "add together all the people in this town to those of the neighbouring town" ex. "add up all the people in this town to those of the neighbouring town"
add (Verb) — Constitute an addition. ex. "This paper will add to her reputation"
add (Noun) — A condition (mostly in boys) characterized by behavioral and learning disorders.