Ci-O

surname · Latin script

Ci-O is a surname written in the Latin script, with more bearers in the Philippines than in any other country.

rarermore common
  • ESSpain1 in 1.1M(measured from records)
  • PHPhilippines≈1 in 1.6M
  • BRBrazil1 in 3.8M

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)

≈69 people, est.

Sources
52 (measured from records)

Highest-authority source

1 in 1.1M (inferred from the name graph)

Spain

measured from records inferred from the name graph

Name dossier (print, CSV)

Spellings & scripts(measured from records)

One other spelling is counted as the same name:

Locally spelled Cio in GB United Kingdom, US United States and Ciò in IT Italy.

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)

recorded in Korean

[사회], 산업별 조직 회의, Congress of Industrial Organization

Sources 2

  • 국립국어원 외래어 표기 용례 자료 (NIKL loanword/foreign-name transcription examples)
  • Skok, Etimologijski rječnik hrvatskoga ili srpskoga jezika (1971-74)

Where in the world(measured from records)

Ci-O 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 Ci-O is recorded, by country
CountryMost common spellingSources
PH Philippines≈69 est.≈1 in 1.6M—Ci-O12
BR Brazil561 in 3.8M56—1
ES Spain441 in 1.1M44—7
GB United Kingdom———Cio11
US United States——listedCio52
IT Italy——listedCiò11

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: IBGE — Censo 2022 Nomes no Brasil per-token lookup (v3 API, given+surname); INE — Padrón per-token widgets (current living counts, given + apellidos); INE — Apellidos más frecuentes (Padrón Municipal). 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).

Other names spelled this way(inferred from the name graph)

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

  • Portuguese surname23 spellings in the group

    Most recorded in Brazil, United States, Chile, Argentina

    Languages: Portuguese, Spanish

    Also written Cius, Cio, Ció, Cío, Çio

  • Swahili surname2 spellings in the group

    Most recorded in Philippines

    Also written Cio

  • French surname9 spellings in the group

    Most recorded in Philippines, France

    Also written Ció, Ciò, Çiõ, Cio, Çïô

  • Italian surname8 spellings in the group

    Most recorded in Italy

    Also written Ciò, Cius, Ció, Cio, Cío

6 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.

Evidence(measured from records)

No register attests this spelling yet

None of the official registers or reference works in our corpus lists Ci-O 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

In which country does Ci-O have the most bearers?
Mondonomo estimates about 69 people named Ci-O in the Philippines, more than in any other country we hold, where it is most often spelled ci-o.
Where is Ci-O most common?
Measured as a share of residents rather than as a count, Ci-O is densest in Spain — about 1 in 1.1 million people — even though Philippines holds more of our records for it.
How common is the name Ci-O?
In Brazil, the national register counted 56 people named Ci-O, about 1 in 3.8 million residents.

What do you want to know about Ci-O?

Nobody replies to these one by one, but what readers ask decides what these pages answer next.

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Query this name via API
curl -H "X-API-Key: YOUR_KEY" https://api.mondonomo.ai/api/v1/name-graph/ci-o

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, “Ci-O”. Data snapshot 2026-10-10.

See how Ci-O parses inside a full name →