Caius

given name · Portuguese · Latin script

Recorded as a male name· opposite-gender records fall within measured source noise

Caius is a given name, with more bearers in Brazil than in any other country. It appears chiefly in Portuguese and English, written in the Latin script. Recorded meaning: Ellipsis of Gonville and Caius College, Cambridge.

rarermore common
  • BRBrazil1 in 739
  • BOBolivia1 in 1.9K
  • PEPeru1 in 6.7K

carrying the name, one hue, darker where it is more common. Hover a country for its figure.

≈289K

across 6 countries

#809

of 16M given names

2

recorded for this name

Sources
230

206K records

Official registry-verified

1 in 739

Brazil

Spellings & scripts

CaioLatin · Portuguese3.2M records
КайоCyrillic · Russian72 records

One other spelling is counted as the same name:

Locally spelled Caio in BR Brazil, US United States, GB United Kingdom and 7 more, Cayo in AR Argentina, PE Peru, CL Chile and 6 more, Gaius in NG Nigeria, SG Singapore, BE Belgium and Cajus in DE Germany.

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

Meaning & origin

Ellipsis of Gonville and Caius College, Cambridge.

Sources 1

  • kaikki.org Wiktionary extract (IPA + transliterations)

Attested across 21 languages in the etymology graph.

Where in the world

Sorted by bearers counted by national registers, records where none counts.

Where Caius is recorded, by country
CountryMost common spellingSources
BR Brazil#154286,597116K rec.1 in 739287KCaio230
AR Argentina40,82227K rec.7KCayo53
PE Peru36,06043K rec.Cayo65
CL Chile4,350592 rec.1Cayo50
BO Bolivia3,2802.4K rec.Cayo29
EC Ecuador1,68054 rec.32Cayo20
US United States1,2997.2K rec.1 in 256K1.3KCaio194
NG Nigeria1,1682.1K rec.Gaius44
MX Mexico1,0801.2K rec.Cayo33
GB United Kingdom728495 rec.3Caio58
PT Portugal#739712237 rec.listedCaio69
CA Canada615192 rec.5Caius36

Roughly 287K people in Brazil bear this name (about 1 in 739). Estimates project the name's share of our records onto national population, so each is only as good as the record base beside it — the Basis column gives that base; rows marked rest on fewer records than the estimate itself and are order-of-magnitude at best.

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

Languages

  • Portuguese1.9K33%
  • English1.7K29%
  • Finnish73313%
  • German2675%
  • Romanian2274%
Show as table
Languages in which the name is recorded
NameRecordsNote
Portuguese1,87433%
English1,68729%
Finnish73313%
German2675%
Romanian2274%

Language is read off each record's context, not declared by the bearer; a share is of all records for this spelling.

Other names spelled this way

Caius is also recorded as 4 other names, grouped separately because the records behind them do not connect to the one described above.

  • French given name743 records spelled Caius14 spellings in the group

    Most recorded in France, United States, Belgium, Congo - Kinshasa

    Also written Gai, Gaï, Caïus, Gái, Gaioz

  • Italian given name89 records spelled Caius10 spellings in the group

    Most recorded in Italy, Philippines, United States, Nigeria

    Languages: Italian, Spanish, Portuguese

    Also written Gaius, Gaio, Gaiò, Gaïus, Gaïo

  • Danish given name63 records spelled Caius14 spellings in the group

    Most recorded in Denmark, United States, Norway, Italy

    Languages: Danish, Swedish, Norwegian

    Also written Gaius, Gåìûs, Gajus, Gaïus

  • Polish given name15 records spelled Caius5 spellings in the group

    Most recorded in Poland

    Also written Kajus, Kajusz, Kajuś, Kájuš

38 further groups record this spelling and are not listed here.

Grouping is the name graph's, not a register's: two spellings join a group when the evidence links them, so a group is a claim about the records rather than about the people.

Other recorded senses

Caius is also recorded in 3 other lexicons, as a different name or as an ordinary word. These are senses of the spelling, not of the name above.

  • In English, Gonville and Caius College,

    as a namePronouncing Dictionary of Proper Names

  • In English, Cambridge University

    as a namePronouncing Dictionary of Proper Names

  • In Latin, alternative form of Gāius

    as a wordkaikki.org Wiktionary extract (IPA + transliterations)

Ordered by how much of this spelling's record each language holds, so a sense from a language the name is barely used in sits last rather than first.

Over time

0100200300200020102020

Show as table
Caius in SSA — National Baby Names (1880–present), United States, 1994–2025
Yearrecords
19945
19997
200010
200116
200213
200315
200414
200523
200615
200729
200827
200943
201049
201144
201274
2013109
2014124
2015138
2016153
2017110
2018130
2019137
2020156
2021138
2022150
2023140
2024206
2025254

US SSA — National Baby Names (1880–present)28 years between 1994–2025. One register's own figures, never a sum across registers: two registers counting the same people would double them.

Notable people with this name

1400160018002000Caius of Korea, b. 1571Caius Gabriel Cibber, b. 1630Caius Brediceanu, b. 1879Caius Welcker, b. 1885Caius Parellada i Cardellach, b. 1911Caius Iacob, b. 1912Caius Spronken, b. 1958Caius Dobrescu, b. 1966Caius Lungu, b. 1989

The ten people covered by the most Wikipedia language editions — a proxy for cross-cultural notability, which favours historical and Western figures over equally prominent contemporary ones — shown by birth year. Source: Wikidata (CC0).

Evidence

Attested in 41 sources across 23 countries.

Official registers attesting Caius
CountryRegisterYearCountRank
US United StatesCensus Bureau — First Name Frequency 2020 by sex20201.2K#10,848
US United StatesSSA — National Baby Names (1880–present)2025254
FI FinlandDVV — Nimipalvelu (Finnish name service, per-name lookup)181#3,685
FI FinlandDVV — Etunimitilasto (Finnish given names register)152
BR BrazilIBGE — names by decade (Kaggle mirror)2022130
BR BrazilIBGE — Censo 2022 Nomes no Brasil per-token lookup (v3 API, given+surname)129#34,267
BR BrazilBrasil.IO genero-nomes (IBGE Censo 2010 mirror, CC-BY-SA)125#16,049
BR BrazilIBGE — Nomes (census name API)111#34,468
CA CanadaStatistics Canada — First names at birth by sex at birth (Table 17-10-0147-01)202027
CA CanadaStatistics Canada — First names at birth by sex at birth (Table 17-10-0147-01)201926
CA CanadaStatistics Canada — First names at birth by sex at birth (Table 17-10-0147-01)201326
CA CanadaStatistics Canada — First names at birth by sex at birth (Table 17-10-0147-01)201425

Reference works 2

  • Wikipedia given-name tokens
  • Wikidata name items (native-script + romanized given/family names)

These works list the name; their figures are licensed and are not reproduced here.

Register rows as of the 2026-09-12 data build · 141 rows in the corpus for this spelling.

Frequently asked questions

How common is the name Caius?
We estimate roughly 289 thousand people bear Caius (counting its spellings and scripts) across 6 countries in our records.
In which country does Caius have the most bearers?
We estimate about 287 thousand people bear Caius in Brazil, more than in any other country in our records, where it is most often spelled caio.
Where is Caius most common?
Caius is densest in Brazil, where the national register counts about 1 in 739 people carrying it.
How common is Caius compared with other names?
In Brazil, Caius is the 154th most common given name of 536,280 given names recorded there.
Is Caius a male or female name?
Caius is a male name in our records. Opposite-gender entries fall within the cross-gender noise we measure in the source data, so we don't report them as usage.
What does the name Caius mean?
Recorded meaning: Ellipsis of Gonville and Caius College, Cambridge.
Query this name via API
curl https://api.mondonomo.ai/api/v1/name-graph/caius

The same payload this page is built from: spellings and scripts, countries and languages, related names, and the registers that attest the form. Rate-limited for casual use. Bulk access and licensing.

About this data

measured from records inferred from the name graph machine-generated

Data snapshot . Figures are rebuilt periodically and will change.

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, “Caius” — the 154th most common given name in Brazil. Data snapshot 2026-09-12.

See how Caius parses inside a full name →