Historical Meaning (OED)
Historically, “right” referred to what was just, proper, lawful, or due.
The modern sense of “a right” as an individual entitlement developed through Roman ius, medieval law, and 17th–18th-century natural-rights philosophy. Thinkers like John Locke framed rights as inherent possessions by virtue of being human, rather than gifts from the state. At its core, a right marked a sphere of individual freedom that others, especially government, had a duty not to violate.