rex

/ˈɹɛks/

//ˈɹɛks// noun

"rex" is a 3-letter English headword indexed on PlainSpell.

The verdict

“rex” sits in 20 confusable pairs (corpus #8,478) as a noun. The look-alike neighbours are the real trap.

#8,478
frequency rank, English
3,094
“R” headwords
20
confusable pairs

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - A king, particularly in ancient Rome.

Corpus desk

Index EN-rex · rex · English

rex · rank #8,478 · 0 variants · 20 confusables

  • FREQ-COMMON #8,478
  • LEN-MID 3 letters
  • VOW-1 1 vowel
  • CONFUS-HIGH 20 pairs
  • VAR-0 0 variants
  • BOOK-MID 3,094
  • PHOTO-FINISH resting

Nearest frequency peer: resting (-1 rank slots)

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.

Frequency neighbourhood for “rex”

Lower corpus rank = more everyday usage (inverted bar length for readability)

corpus weight

What this shows Bars show where “rex” sits against the nearest ranked English headwords in the FrequencyWords band, not a reprint of letter-browse containment.

Source FrequencyWords open word-frequency list As of September 3, 2026

Visual similarity to commonly confused words

How many letter changes separate each confused pair (Levenshtein distance, normalized).

rex vs RS
0% similar
rex vs RT
0% similar
rex vs RM
0% similar

Source: PlainSpell confusable corpus (Wiktionary, CC BY-SA).

Key facts for rex
PropertyValue
Headwordrex
LanguageEnglish
Part of speechNoun
IPA/ˈɹɛks/
Letters3
Frequency rank#8,478
Misspellings tracked0
Confusable pairs20
SourceWiktionary (kaikki.org)

Where “rex” sits in English frequency

Every-word frequency runs from the handful of words we use constantly (left) to the long tail used once in a blue moon (right).rex lands here:

#1#100#1K#10K#100K
← used constantlyrarely used →

The axis is logarithmic, with each marked tick roughly ten times rarer than the last. Source: FrequencyWords open word-frequency list.

Easy to mix with look-alikes

The spelling risk for rex is neighbouring look-alikes ("RS", "RT", …), not just typos; it is anoun pronounced /ˈɹɛks/. Frequency #8,478 among 3,094 “R” headwords. 2 recorded senses keep meaning in play.

We couldn't generate a plausible misspelling set for rex, typically a sign the spelling maps closely to how the word sounds. It also participates in 20 confusable-pair relationships, "RS", "RT", "RM", and more, since the words sound or look close enough that writers reach for the wrong one mid-sentence.

Etymologically, the entry records: From Latin rēx (“king”), referring originally to rabbits of the Belgian "castorrex" breed, so named because their fur was similar to that of beavers. Entered English around 1920. Doublet of rajah and roy. The correct English form is rex, spelled R-E-X.

Definition

  1. 1
    A king, particularly in ancient Rome.
  2. 2
    An animal which has a genetic recessive variation that causes the guard hairs to be very short or fully lacking.

Recorded use

Wiktionary example

These source excerpts show how rex appears in context. They illustrate usage; the definition above remains the entry’s reference meaning.

  1. And though the sturdy patrician nobility had already gained ground, though the reges attempted gradually to enlarge the scope of their functions—all this does not change the elementary and fundamental character of the constitution, and this alone is essential.

Etymology

From Latin rēx (“king”), referring originally to rabbits of the Belgian "castorrex" breed, so named because their fur was similar to that of beavers. Entered English around 1920. Doublet of rajah and roy.

Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA); frequency ordering uses the FrequencyWords open word-frequency list (2018 English corpus, MIT). See the methodology for how each field is sourced and updated.

PlainSpell is rendered directly from structured Wiktionary extracts and open word-frequency lists, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of September 3, 2026. Primary sources: Wiktionary (via kaikki.org) and FrequencyWords.

Frequently Asked Questions

How do you spell "rex"?
"rex" is spelled R-E-X. The IPA pronunciation is /ˈɹɛks/.
What does "rex" mean?
As a noun, "rex" means: A king, particularly in ancient Rome.
What words are commonly confused with "rex"?
"rex" is commonly confused with "RS", "RT", "RM". These words look or sound similar but have different meanings. PlainSpell provides detailed comparisons for each pair.
How do you pronounce "rex"?
The IPA (International Phonetic Alphabet) transcription for "rex" is /ˈɹɛks/. Click the speaker icon on the pronunciation badge above to hear it spoken aloud where audio is available.
What is the origin of the word "rex"?
From Latin rēx (“king”), referring originally to rabbits of the Belgian "castorrex" breed, so named because their fur was similar to that of beavers. Entered English around 1920. Doublet of rajah and roy. 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.

Similar English words by spelling shape

Same letter count and similar misspelling depth for "rex", not the corpus desk frequency band.

Same letter count

Frequency-ranked English headwords with 3 letters (nearest by frequency rank).

What to do next

You've looked up "rex". Here's where to go from here.

  • "rex" maps to 20 confusable pairs in this vintage; the highest-scored is "RS". View pair
  • Usage frequency rank #8,478 among English headwords in this corpus. Corpus statistics
  • Browse more English words in the "R" letter cohort. R–Z browse
  • PlainSpell rotates a curated Word of the Day from the English corpus, a passive way to discover vocabulary. Word of the Day

PlainSpell is a reference corpus, not spelling advice. Verify unusual forms in context.

Data Source

Wiktionary (via kaikki.org), licensed under CC BY-SA & GFDL. Word ordering uses an open word-frequency list; misspelling variants are generated by edit-distance from the correct headword.

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

Source: FrequencyWords open word-frequency list