In biological terms, a community is a group of interacting organisms sharing an environment. In human communities, intent, belief, resources, preferences, needs, risks, and a number of other conditions may be present and common, affecting the identity of the participants and their degree of cohesiveness.

In sociology, the concept of community has caused infinite debate, and sociologists are yet to reach agreement on a definition of the term. There were ninety-four discrete definitions of the term by the mid-1950s. Traditionally a "community" has been defined as a group of interacting people living in a common location. The word is often used to refer to a group that is organized around common values and social cohesion within a shared geographical location, generally in social units larger than a household. The word can also refer to the national community or global community.

Communis comes from a combination of the Latin prefix com- (which means "together") and the word munis probably originally derived from the Etruscan word munis- (meaning "to have the charge of"). Since the advent of the Internet, the concept of community no longer has geographical limitations, as people can now virtually gather in an online community and share common interests regardless of physical location.

Gemeinschaft and Gesellschaft

main: Gemeinschaft and Gesellschaft German sociologist Ferdinand Tönnies distinguished between two types of human association: Gemeinschaft (usually translated as "community") and Gesellschaft ("society" or "association"). In his 1887 work, Gemeinschaft and Gesellschaft, Tönnies argued that Gemeinschaft is perceived to be a tighter and more cohesive social entity, due to the presence of a "unity of will." He added that family and kinship were the perfect expressions of Gemeinschaft, but that other shared characteristics, such as place or belief, could also result in Gemeinschaft. Gesellschaft, on the other hand, is a group in which the individuals who make up that group are motivated to take part in the group purely by self-interest. He also proposed that in the real world, no group was either pure Gemeinschaft or pure Gesellschaft, but, rather, a mixture of the two.

Social capital

main: Social capital If community exists, both freedom and security may exist as well. The community then takes on a life of its own, as people become free enough to share and secure enough to get along. The sense of connectedness and formation of social networks comprise what has become known as social capital.

Social capital is defined by Robert D. Putnam as "the collective value of all social networks (who people know) and the inclinations that arise from these networks to do things for each other (norms of reciprocity)." Social capital in action can be seen in no groups what so ever, including neighbours keeping an eye on each others' homes. However, as Putnam notes in Bowling Alone: The Collapse and Revival of American Community (2000), social capital has been falling in the United States. Putnam found that over the past 25 years, attendance at club meetings has fallen 58 percent, family dinners are down 33 percent, and having friends visit has fallen 45 percent.