Solidarity or solidarism is an awareness of shared interests, objectives, standards, and sympathies creating a psychological sense of unity of groups or classes. Solidarity does not reject individuals and sees individuals as the basis of society. It refers to the ties in a society that bind people together as one. The term is generally employed in sociology and the other social sciences as well as in philosophy and bioethics. It is a significant concept in Catholic social teaching and in Christian democratic political ideology. Although being interconnected concepts, solidarity, by contrast to charity, takes a systems change approach.

A society is a group of individuals involved in persistent social interaction or a large social group sharing the same spatial or social territory, typically subject to the same political authority and dominant cultural expectations. Societies are characterized by patterns of relationships between individuals who share a distinctive culture and institutions; a given society may be described as the sum total of such relationships among its constituent members.