addition
noun
uk/əˈdɪʃən/ us [ C ]
something extra that is added to something:
an addition to sth The company provides a compensation package which amounts to an addition to the employee's salary.
[ U ]
the act of adding something to something else:
the addition of sth to sth The addition of women to the board was a deliberate diversity strategy.
[ C ] US ( UK extension)
a new part added to a building:
an addition to/on sth The commissioners plan to build an addition on the front of the building.
in addition to sth
used for saying that something else exists or is included:
In addition to movies, the company also published magazines.