Etymology Map
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Rational

2 stages from Latin to English.

Today it means based on reason

Where does the word "rational" come from? It comes from Latin rationalis, adopted directly into English (1300s).

1
Stage 1 of 2
rationalis
Latin · ancient
"of reason"
from 'ratio', reason
2
Stage 2 of 2
rational
English · 1300s
"reasonable"
'rational numbers' date from the 1500s
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Read the full story

Rational’s story begins in Latin: rationalis meant “of reason.” From 'ratio', reason. It reached English by 1300s as rational. 'rational numbers' date from the 1500s. Today, rational means based on reason.