Oppression is the systematic mistreatment of a group by people and institutions with more power. It differs from individual prejudice because it is built into laws, economies and cultural norms that keep one group on top.
Philosopher Iris Marion Young described five faces of oppression in 1990: exploitation, marginalization, powerlessness, cultural imperialism and violence. Philosopher Marilyn Frye compared oppression to a birdcage. Any one wire seems harmless, but together they trap the bird.
In the US, oppression has taken legal form in chattel slavery, Indigenous removal, Jim Crow, the Chinese Exclusion Act and the denial of rights to women and LGBTQ people. Today it lives in gaps in wealth, health, policing and political power. Oppression also overlaps. Intersectionality, a framework named by Kimberlé Crenshaw, explains how racism, sexism and other systems combine to shape people's lives.