Rēx

surname · Latin script

Rēx is a surname written in the Latin script, with more bearers in the Philippines than in any other country. Recorded meaning: From the 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.

  • PHPhilippines≈1 in 1.3K(inferred from the name graph)
  • NZNew Zealand≈1 in 3.1K
  • HKHong Kong≈1 in 3.7Kfew records

carrying the name, as counted by its national register where one exists and as Mondonomo estimates it elsewhere (marked ≈ and "est." on hover). One hue, darker where it is more common; hover a country for its figure.

Philippines (inferred from the name graph)

≈88,000 people, est.

Record sources
476 (measured from records)

corpus datasets behind its best-documented spelling

strongest: highest-authority source

≈1 in 1.3K (inferred from the name graph)

Philippines, est.

measured from records inferred from the name graph

Spellings & scripts

(measured from records)

One other spelling is counted as the same name:

Locally spelled Rex in US United States, PH Philippines, GB United Kingdom and 6 more.

Spellings marked ● are how people bearing the name write it in our records, and ○ marks a model's transliteration; click a spelling to open its page.

Meaning & origin

(measured from records)

From the 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.

Cited for this meaning 5

  • A concise dictionary of first names
  • DUDEN Lexikon der Vornamen
  • 국립국어원 외래어 표기 용례 자료 (NIKL loanword/foreign-name transcription examples)
  • Wiktionary
  • Nordic Names

Attested across 22 languages in the etymology graph.

Where in the world

(measured from records)

Rēx counted together with the spellings and other-language forms grouped with it. Where a register counted another spelling, the row names it.

Sorted by bearers: national registers' counts, and Mondonomo's estimates (≈, est.) where no register counts.

Where Rēx is recorded, by country
CountryMost common spellingSources
PH Philippines#367≈88,000 est.≈1 in 1.3K—Rex125
US United States#82036,1661 in 9.2K36KRex476
NG Nigeria—≈12,000 est.≈1 in 20K—Rex74
GB United Kingdom#870≈6,000 est.≈1 in 12K9Rex189
CA Canada#844≈4,800 est.≈1 in 8.7K9Rex155
AU Australia#747≈4,200 est.≈1 in 6.5K9Rex180
HK Hong Kong#720≈2,000 est.≈1 in 3.7K—Rex45
NZ New Zealand#320≈1,700 est.≈1 in 3.1K11Rex105
SG Singapore#476≈1,200 est.≈1 in 5.1K—Rex48

Exact figures are national registers' own counts, while figures marked ≈ and est. are Mondonomo’s estimates, counted from our sources and calibrated against those registers; hover one for how far to trust it in that country. A dash means neither exists.

Registers cited: Census Bureau — First Name Frequency 2020 by sex; NRS — Baby names Scotland full list (1974–present); Australian national given names (aggregated state BDM); Alberta Open Government — Frequency and Ranking of Baby Names by Year and Gender; DIA — Baby name popularity (1900–present). Figures without a register are Mondonomo estimates; see Methodology.

Country figures for a list of names, at full precision, are available under licence rather than by scraping this table (how that works).

Evidence

(measured from records)

No register attests this spelling yet

None of the official registers or reference works in our corpus lists Rēx under this spelling. The statistics on this page rest on person records, and the related names are inferred from the name graph.

Frequently asked questions

What does the name Rēx mean, and where does it come from?
From the 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. Recorded by A concise dictionary of first names and DUDEN Lexikon der Vornamen and 3 other sources.
Which countries have the most people named Rēx?
Mondonomo estimates about 88 thousand people named Rēx in the Philippines, more than in any other country we hold, where it is most often spelled rex. After it come United States, Nigeria, United Kingdom and Canada; the country table on this page ranks them.
How common is the name Rēx?
In the United States, the national register counted 36,166 people named Rēx in 2020, about 1 in 9.2 thousand residents.
How common is Rēx compared with other names?
In the Philippines, Rēx is the 367th most common given name of 486,299 given names recorded there.

What do you want to know about Rēx?

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Query this name via API
curl -H "X-API-Key: YOUR_KEY" https://api.mondonomo.ai/api/v1/name-graph/r%C4%93x

The payload this page is built from: spellings and scripts, countries and languages, related names, and the registers that attest the form. It takes a free API key (1,000 requests a day), which returns what this page shows everyone; the full country table, every register citation and the year-by-year series come with a licensed key, as does bulk access.

About this data

measured from records inferred from the name graph machine-generated

These figures come from the data snapshot of and will change as it is rebuilt.

Statistics are aggregated from the Mondonomo name corpus; related names and etymology are inferred from the name graph; pronunciation and any machine-marked transliterations are model-generated. Read how the numbers are made, including their known failure modes, and where the data comes from.

Reference works we consult — surname dictionaries, official name registers, Wikidata and Wiktionary — are named directly, beside the claims they support. The per-country source counts also include datasets of person records: we publish how many there are and their authority tier, but not their names.

Cite this page Mondonomo, “Rēx” — the 367th most common given name in the Philippines. Data snapshot 2026-10-13.

See how Rēx parses inside a full name →