l) KEY ADJECTIVE:
- Having or exercising the ability to reason.
- Of sound mind; sane.
- Consistent with or based on reason; logical: rational behavior. See Synonyms at logical.
- Mathematics Capable of being expressed as a quotient of integers.
- A rational number.
Middle English racional
, from Old French racionel
, from Latin ratinlis
, from rati, ratin-
; see reasonOTHER FORMS:ration·al·ly(Adverb)