rational

B1 Topic:Mind & Cognition

US /ˈɹæʃ(ə)nəl/ See IPA manual

Freq #7692

Meanings

1

adj
Based on clear, sensible thinking rather than emotion.

We need a calm, rational discussion about the problem.
2

adj
Able to think clearly and reason.

Humans are rational creatures.
3

adj
(mathematics) Able to be written as a fraction of two whole numbers.

One half is a rational number, but the square root of two is not.

Thesaurus

Opposites

absurdarationalarbitrary irrationalnon-rationalnonsensical

Word family

Forms rationals

Derived forms antirationalbiorationalbirationalcontrarationalextrarationalhyperrationalnonrationaloverrationalprerationalpreterrationalpseudorationalratfor

Related forms arationalirrationalnon-rationalrationale rationalityrationalnesssubrationalsuprarational

Etymology

From Old French rational, from Medieval Latin rationale (“a pontifical stole, a pallium, an ornament worn over the chasuble”), neuter of Latin rationalis (“rational”), for which see the first etymology. Translation of λογεῖον (logeîon) or perhaps λόγιον (lógion, “oracle”) in the Septuagint version of Exodus 28.

rational Old French rationalis Latin

View etymology graph ->

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# rational

**Type:** Word
**Level:** B1
**Part of speech:** adj
**IPA (US):** /ˈɹæʃ(ə)nəl/
**Frequency rank:** 7692

## Meanings
1. Based on clear, sensible thinking rather than emotion.
2. Able to think clearly and reason.
3. (mathematics) Able to be written as a fraction of two whole numbers.

## Examples
- We need a calm, rational discussion about the problem.
- Humans are rational creatures.
- One half is a rational number, but the square root of two is not.

## Antonyms
- absurd
- arational
- arbitrary
- irrational
- non-rational
- nonsensical

## Derived Forms
- antirational
- biorational
- birational
- contrarational
- extrarational
- hyperrational
- nonrational
- overrational
- prerational
- preterrational
- pseudorational
- ratfor

## Related Forms
- arational
- irrational
- non-rational
- rationale
- rationality
- rationalness
- subrational
- suprarational

## Roots and Affixes
- Root: rational
- Root: rationalis

## Etymology
From Old French rational, from Medieval Latin rationale (“a pontifical stole, a pallium, an ornament worn over the chasuble”), neuter of Latin rationalis (“rational”), for which see the first etymology. Translation of λογεῖον (logeîon) or perhaps λόγιον (lógion, “oracle”) in the Septuagint version of Exodus 28.

## AI Etymology
Rational comes from Old French rational, from Medieval Latin rationale (“a pontifical stole, a pallium, an ornament worn over the chasuble”), neuter of Latin rationalis (“rational”), for which see the first etymology. Translation of λογεῖον (logeîon) or perhaps λόγιον (lógion, “oracle”) in the Septuagint version of Exodus 28. Modern senses include based on clear, sensible thinking rather than emotion. and able to think clearly and reason.. The wider word family includes derivatives such as antirational, biorational, birational, contrarational, extrarational, and hyperrational and related forms such as arational, irrational, non-rational, and rationale.

## Topics
- Mind & Cognition

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rational

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