This entry presents solidarity as a material and relational practice shaped by the entangled conditions of postdigital life. Rather than a moral ideal, solidarity is understood as an active response to the colonial, historical, and technological structures that mediate connection. The entry examines how solidarity is formed through digital mediation, enacted across distributed networks, and sustained through imaginative work that keeps open the possibility of alternative futures. Emphasis is placed on the labour that underpins collective existence and the need for practices that acknowledge asymmetry, responsibility, and interdependence within contemporary social and technological arrangements.