add on

add on
1) PHRASAL VERB: usu passive If one thing is added on to another, it is attached to the other thing, or is made a part of it.

[V n P] Holidaymakers can also add on a week in Majorca before or after the cruise...

[V-ed P] To the rear is a large dining room - added on early this century.

2) PHRASAL VERB If you add on an extra amount or item to a list or total, you include it.

[V P n (not pron)] Many loan application forms automatically add on insurance. [Also V n P]

English dictionary. 2008.