reason

Where does the word "reason" come from? It comes from Latin ratio, passing through Old French before entering English (1200s).

Reason’s story begins in Latin: ratio meant “reckoning, reason.” From 'reri', to reckon. By medieval, the word had taken hold in Old French as raison. The Latin t softened in French. It reached English by 1200s as reason. The Age of Reason referred to the 1700s. Today, reason means a cause or explanation; the power to think logically.

1. Stage 1 · Latin · ancient ratio "reckoning, reason", from 'reri', to reckon.
2. Stage 2 · Old French · medieval raison "reason", the Latin t softened in French.
3. Stage 3 · English · 1200s reason "the power of thought", the Age of Reason referred to the 1700s.