rational number

noun

"rational-number" is a 14-letter English headword indexed on PlainSpell.

The verdict

“rational number” is uncommon English (outside the top frequency list), classed as a noun. The kind of spelling people second-guess.

Unranked
below top-frequency English
15
letters

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - A number that can be expressed as the ratio of two integers.

Corpus desk

Index EN-rational-number · rational number · English

rational number · unranked · 0 variants · 0 confusables

  • FREQ-UNRANKED Unranked
  • LEN-MEGA 15 letters
  • VOW-6 6 vowels
  • CONFUS-0 No pairs
  • VAR-0 0 variants
  • BOOK-THIN "R" thin
  • PHOTO-UNK Peer pending

Read with this headword: Spelling guide for this pattern

Desk codes from Wiktionary headword shape, FrequencyWords rank tier, confusable-pair count, generated misspelling depth, letter-cohort book size, and photo-finish peer. Not a difficulty grade.

Key facts for rational number
PropertyValue
Headwordrational number
LanguageEnglish
Part of speechNoun
Letters15
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Long-tail rank of “rational number” in English

rational numberranks outside the top 100,000 English headwords, in the long tail of specialist, archaic, or seldom-used vocabulary, exactly the territory where a reader stops mid-sentence to double-check spelling.

Beyond rank #100,000. Source: FrequencyWords open word-frequency list.

Rare enough to double-check

rational number is uncommon English outside the top frequency list, classed as anoun. Rarity is why readers land here mid-draft. Gloss: "A number that can be expressed as the ratio of two integers.".

rational number has no tracked misspelling variants, since its letter sequence doesn't invite the usual edit-distance slips. We don't track a confusable pairing for this entry, since no other headword is close enough in sound or shape to pair with it.

Etymologically, the entry records: From rational + number, ultimately from Latin rationalis + numerus. Compare analogous logarithm, from Ancient Greek. The correct English form is rational number, spelled R-A-T-I-O-N-A-L- -N-U-M-B-E-R.

Definition

  1. 1
    A number that can be expressed as the ratio of two integers.

Etymology

From rational + number, ultimately from Latin rationalis + numerus. Compare analogous logarithm, from Ancient Greek.

Antonyms

This word in other languages

Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA). See the methodology for how each field is sourced and updated.

Frequently Asked Questions

How do you spell "rational number"?
"rational number" is spelled R-A-T-I-O-N-A-L- -N-U-M-B-E-R.
What does "rational number" mean?
As a noun, "rational number" means: A number that can be expressed as the ratio of two integers.
What is the origin of the word "rational number"?
From rational + number, ultimately from Latin rationalis + numerus. Compare analogous logarithm, from Ancient Greek. See the full etymology section above for more details.
Is PlainSpell free to use?
Yes, PlainSpell is a completely free word reference. You can look up definitions, pronunciations, confusable pairs, homophones, and spelling corrections across 5 languages without any sign-up or subscription.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list