Definition: This term has two meanings in sociology. In the first sense, an aggregate is a sum of individual characteristics, experiences, or behaviors that is used to reflect a collective phenomena for an entire population. If we add together all of the individual acts of murder that take place in a year, for example, the result is an aggregation that tells us something about the society in which the murders occurred.
In the second sense, an aggregate is a collection of people that can be thought of as a whole simply because they happen to be in the same place at the same time. Pedestrians walking along a street, for example, are an aggregate. What distinguishes aggregates from other collections of people (such as a group or social category) is that all that is needed for an aggregate to exist is physical proximity.