There are many definitions of social enterprises. Here are two of my favorites:
Social enterprises are private organizations dedicated to solving social problems, serving the disadvantaged and providing socially important goods that were not, in their judgment, adequately provided by public agencies or private markets. These organizations have pursued goals that could not be measured simply by profit generation, market penetration, or voter support.
~ J. Gregory Dees (quoted in J. Kickul & T.S. Lyons, Understanding Social Entrepreneurship: The Relentless Pursuit of Mission in an Ever Changing World (2012))
Social enterprises trade for a social purpose. They combine innovation, entrepreneurship and social purpose and seek to be financially sustainable by generating revenue from trading. Their social mission prioritizes social benefits above financial profit, and if and when a surplus is made, this is used to further the social aims of the beneficiary group or community, and not distributed to those with a controlling interest in the enterprise.
~H. Haugh, The Role of Social Enterprise in Regional Development, 2 Int’l J. Entrepreneurship & Small Bus. 346 (2005) ( also quoted in Kickul & Lyons).