Definition of ADD

Verb: add ad

Make an addition (to); join or combine or unite with others; increase the quality, quantity, size or scope of
"We added two students to that dorm room"; "She added a personal note to her letter"; "Add insult to injury"; "Add some extra plates to the dinner table"
State or say further
"'It doesn't matter,' he added";
- append, supply
Provide a particular quality or character
"The music added a lot to the play"; "This adds a light note to the program";
- lend, impart, bestow, contribute, bring
(arithmetic) make an addition by combining numbers
"Add 27 and 49, please!"; "add together 27 and 49, please!";
- add together
Determine the sum of
"Add all the people in this town to those of the neighbouring town"; "add together all the people in this town to those of the neighbouring town"; "add up all the people in this town to those of the neighbouring town";
- total, tot, tot up, sum, sum up, summate, tote up, add together, tally, add up
Constitute an addition
"This paper will add to her reputation"

Noun: ADD

A condition (mostly in boys) characterized by behavioral and learning disorders
- attention deficit disorder, attention deficit hyperactivity disorder, ADHD, hyperkinetic syndrome, minimal brain dysfunction, minimal brain damage, MBD