Primary groups include people who have long-term, intimate relationships and are usually small, whereas secondary groups are more impersonal, less cohesive and meet for short periods of time. In sociology, a group is a set of individuals who interact repeatedly in a structured way.
The study of social groups is one of the main interests of sociology. The term social group refers to two or more individuals who interact regularly and consider themselves to be a part of a group. An example of a primary group is a family or a married couple, whereas examples of secondary groups include sports societies, co-workers and school peers.