Reclamation is when a marginalised/oppressed group takes a slur or other negative thing used to refer to them, and reclaims it for their own use. For instance, if a woman wears a tshirt saying, "Bitch", she is reclaiming a term usually used as an insult against women. The same applies to slurs and negative terms and symbols used in relation to sexuality and gender identity/expression, race/ethnicity, etc.