Communities of practice
Lave and Wenger (1991) coined the term communities of practice, to capture the importance of activity in binding individuals to communities and of communities to legitimizing individual practices. Roughly, a community of practice involves a collection of individuals sharing mutually defined practices, beliefs, and understandings over an extended time frame in the pursuit of a shared enterprise (Wenger, 1998). Roth (1998) suggested that these communities "are identified by the common tasks members engage in and the associated practices and resources, unquestioned background assumptions,common sense, and mundane reason they share" (p. 10).
The above passage is taken from the Barab, S. A., & Duffy, T. (2000). From practice fields to communities of practice. In D. H. Jonassen and S. M. Land (Eds.) Theoretical Foundations of Learning Environments (pp. 25–56). Mahwah, NJ: Lawrence Erlbaum & Associates.