1. [ verb ] determine the sum of
Synonyms: add add_up total tot_up summate tally sum_up sum tote_up tot

"Add all the people in this town to those of the neighboring town"

Related terms: count add sum sum count sum summation
2. [ verb ] (mathematics) make an addition by combining numbers
Synonyms: add

"Add 27 and 49, please!"

Related terms: subtract calculate foot arithmetic total total adder