Religion

Latin religio — obligation, bond, reverence. Etymology disputed: possibly from religare (to bind again) or relegere (to re-read, to go over again). The binding sense and the careful observation sense both fit — religion as both obligation and practice.

The category of 'religion' as distinct from politics, law, and science is itself a modern Western construction. Many traditions do not separate sacred from secular in ways the word assumes. 'Religious freedom' in American law requires defining what counts as religion — an ongoing legal and political negotiation.