Aggregate function

In database management an aggregate function is a function where the values of multiple rows are grouped together as input on certain criteria to form a single value of more significant meaning or measurement such as a set, a bag or a list.

Common aggregate functions include :

Aggregate functions are common in numerous programming languages, spreadsheets, and relational algebra.

https://msdn.microsoft.com/en-IN/library/ms173454.aspx

...
Wikipedia