(physics) The mechanics of objects moving at velocities comparable to the speed of light; is compatible with the special and general theories of relativity.

(law) A situation in which an institution has encouraged its customers to become reliant on their services, and is therefore legally obligated to continue to provide those services.

A person who is relation through birth, as opposed to marriage or adoption.

The peaceful coexistence of multiple religions in a community / Ecumenism

A SUMO protein

(set theory) A partial order.

The act of relinquishing something.

(mathematics, rare) A total order.

In a reliable manner.

(idiomatic) A relationship following a prior long-term relationship, usually short in duration and used to help mend the "broken heart".