Erik Olin Wright defines the solidarity economy.

The social and solidarity economy is an umbrella term covering a range of economic activities and organizations that are anchored in communities, embody egalitarian and solidaristic values, and are committed to some kind of needs-oriented or social justice mission. Often the organizations within the social/solidarity economy are cooperatives, but they may be other kinds of enterprises: non-profits, mutual [aid] societies, voluntary associations, community organizations, social enterprises (commercial firms with a strong social mission) or even churches. In some parts of the world, the social/solidarity economy overlaps with what is called the “informal economy,” economic activity that falls outside of officially recognized and publicly regulated economic activity. But the social/solidarity economy can also involve durable organizations with permanent staff.

Often the social/solidarity economy emerges in the context of poor and underserved communities as a survival strategy to fill gaps in social provision. When there is a severe economic crisis, as occurred in Argentina in 2000 and Greece in 2009, all sorts of social/solidarity economy activities proliferate: time banking and local currencies; community kitchens; DIY tool libraries; community gardens; caregiving exchanges; free clinics; and much more. However, the social/solidarity economy is not simply a response to marginalization and precariousness; it is also fostered by people trying to build economic relations on a more communitarian, needs oriented basis. The Canadian province of Quebec, for example, has a vibrant social/solidarity economy that includes daycare centers, eldercare and disability services, recycling, performing arts, affordable housing projects, makerspaces, and a diversity of cooperatives. Activists involved in the social/solidarity economy generally see their work as building emancipatory enclaves within capitalism that enable people to live very different kinds of lives.

Source: Erik Olin Wright, How to Be an Anti-Capitalist in the 21st Century, 2019, pp. 79-80.

See also the US Solidarity Economy Network and Urgenci, “the international grassroot network of…regional and Local Solidarity-based Partnerships for Agroecology (LSPAs), of which Community Supported Agriculture (CSA) is the best-known iteration.”