I think community is whatever groups you come in contact with. For example, the school I teach at is a community. It affects me directly, because I spend much of my time there and it definitely affects my viewpoint and how I look at the world. I also belong to a community in which I live, the town and larger urban area. Both of those also affect me, though not as much as my close-knit school.
This might be a good Social Sciences Discussion Forum question.
I define my community as being physical surroundings and the people I regularly encounter within those surroundings. I would include all of the small (under 15,000 population) town in which I live with its houses, businesses, parks, churches, etc. as being my physical community. People I include in my community include the immediate family members in my home, the neighbors and coworkers I see on a nearly daily basis, friends I meet with regularly (worship services at church, coffee-and-conversation weekly gathering), and others who live in my town that I may not know personally but care about because we share proximity of space and concern for the welfare of each other.
The link below bases its definition of community on shared identity. Using that definition, my benchmarks are broader than it recommends, in that it isn't as concerned with the physical environment aspects.
A community is a group of people connected by interest, interacting for a common purpose. This is more of a social view of a community. Sure a community is also considered to a area where people live near one another. But a true community is much bigger and is deeper than that. A true community can exist where ever there are people who are committed to helping one another. A community can exist in a specific area or neighborhood or even a working enviroment. The word come from french word meaning together.