Cassius
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Meaning
“Roman family name, traditionally linked to Latin cassus, 'empty, vain'”
The story
Cassius is a Roman family name, possibly from the Latin cassus, "empty, vain," a meaning its recorded bearers cheerfully ignored. Rome's Cassius helped lead the plot against Julius Caesar; a 3rd-century historian and several early saints carried it too. The American story runs through one man: Muhammad Ali was born Cassius Marcellus Clay Jr. in 1942, named for his father, who was named for the abolitionist Cassius Clay, three bearers deep before the name ever reached a boxing ring. The register kept Cassius rare for decades, 112 in the 1920s, then 309 in the 1960s, just as Cassius Clay was filling the sports pages, and we will let the reader weigh that timing. The real climb is recent: 419 in the 1990s, 1,225 in the 2000s, 3,635 in the 2010s, and 3,279 so far this decade. A name that spent a century as a reference and became a first choice.
How popular is Cassius around the world?
In the United States, 3,301 babies were named Cassius between 2020 and 2025. In England and Wales, 140 boys named Cassius were born in 2025, the 319th most common name among boys that year.
Cassius is on the official records of the United States, England and Wales, Canada, Scotland, Austria and Brazil.
United States
1 in 6,600
In the United States, 3,301 babies were named Cassius between 2020 and 2025.
Shape drawn from US Social Security baby-name records. Cassius peaked in the 2010s and the 2020s in nearly equal measure.
Births with a Social Security record. Source: U.S. Social Security Administration
England and Wales
1 in 4,200
In England and Wales, 140 boys named Cassius were born in 2025, the 319th most common name among boys that year.
share of that year’s name registrations
Birth registrations in England and Wales (not the whole UK); exact spellings are counted separately, and any spelling under 3 in a year is withheld at source. Source: Office for National Statistics, baby names in England and Wales
Canada
1 in 12,000
In Canada, 30 boys named Cassius were born in 2024, the 857th most common name among boys that year.
share of that year’s name registrations
First given names from provincial and territorial vital statistics across Canada; any name-sex-year under 5 is excluded at source, and small Quebec counts carry a randomized adjustment made at source. Shares divide by Statistics Canada’s count of live births for the year; the 2024 count is preliminary. Source: Statistics Canada, first names at birth (table 17-10-0147-01)
Scotland
1 in 15,000
In Scotland, 3 boys named Cassius were registered in 2024, the 727th most common name among boys that year.
The count never rose above 5 in a year, too few to chart.
Births registered in Scotland; different spellings count separately but accents are merged at source, and any spelling under 3 in total is suppressed. Source: National Records of Scotland, babies' first names
Austria
1 in 76,000
In Austria, 1 boy named Cassius was born in 2025, ranked 1,842nd among boys that year, spellings that differ only by special characters counted together.
The count never rose above 1 in a year, too few to chart.
Live births in Austria by year of birth, 1984–2025, from Statistik Austria’s first-name statistics; spellings that differ only by special characters are counted together (umlauts stay apart), every name down to a single birth is published, and the count covers babies with Austrian citizenship only until 2009, every baby from 2010, and from 2015 also births abroad to mothers living in Austria. Shares divide by Statistik Austria’s count of live births from 2010, and before that by the file’s own total for the year. Source: Statistik Austria - data.statistik.gv.at (OGDEXT_VORNAMEN_1, updated 2026-07-09)
Brazil
1 in 170,000
At the 2022 census, 1,287 people in Brazil were named Cassius, ranked 6,985th, with a median age of 41.
Among people named Cassius living in Brazil at the 2022 census, more were born in the 1970s than in any other decade.
people alive at the 2022 census, by decade of birth
People alive and resident in Brazil at the 2022 census, a living-population count, not births; names under 20 are withheld at source. Source: IBGE, Censo Demográfico 2022
Argentina
last on record 2018
Cassius is not on the 2024 record for Argentina, where small counts are withheld at source.
The count never rose above 2 in a year, too few to chart.
Given-name components of births in Argentina 2012–2024; national cells are lower bounds and no sex split is published. Source: RENAPER (Argentina), Dirección Nacional de Población, given names 2012-2024
Montevideo City
last on record 1988
Cassius is not on the 2011 record for Montevideo, whose registry withholds nothing, so the spelling was not given there that year.
The count never rose above 1 in a year, too few to chart.
Births in the department of Montevideo (not all of Uruguay) by first name and year of birth, 1940–2011, from the city’s civil registry, which writes names in capitals, almost always without accents; counted as spelling groups (accent and punctuation variants merged), nothing is withheld at source, and 2012 is excluded as a partial year. Source: Servicio de Registro Civil, Intendencia de Montevideo, Partidas de Registro Civil de Montevideo (Licencia de Datos Abiertos - Uruguay); 2012 dropped as partial
New Zealand
last on record 2023
Cassius is not on the 2025 record for New Zealand, where names under 10 in a year are excluded at source.
share of that year’s name registrations
First given names from New Zealand birth registrations, grouped by registration year; any name under 10 in a year is excluded at source. Shares divide by Stats NZ’s count of births registered to mothers living in New Zealand, under 1% below the registry’s own count. Source: Department of Internal Affairs (New Zealand), baby name popularity over time
South Australia
last on record 2016
Cassius is not on the 2017 record for South Australia, whose registry publishes every name given that year.
The count never rose above 3 in a year, too few to chart.
Births registered in South Australia (not all of Australia) by first name and year of registration, 1944–2017, from the state’s Births, Deaths and Marriages registry, which publishes every name down to a single birth in capitals; a spelling its export repeats inside a year is counted once, and from 2018 only a top 100 is published, so the series ends at 2017. Source: Consumer and Business Services (South Australia), popular baby names
Not on the record in Spain, Mexico City, Puerto Rico, Ireland and Poland: those registries withhold small counts, so rare uses may sit below their floors.
Not on the Chile record: nametree keeps spellings that reached 5 registrations in some year, so rarer uses are not shown. Not on the France record: nametree keeps spellings that reached 20 births in some year, so rarer uses are not shown. Not on Norway’s list: Statistics Norway lists only first names carried by 200 or more living people, so rarer names are not shown.
When you meet Cassius
Most people given the name Cassius in the United States are children or teenagers today. The name belongs to this generation.
Estimated from US Social Security birth registrations and typical lifespans; a rough guide, not a rule.
The Cassius deep dive
Whether you’re naming a baby or exploring your own name’s history, this is a personal letter, not a list: where Cassius truly comes from, how it traveled, and what a century of records reveals. If you have grown a tree on nametree, it also considers how Cassius fits with your family’s names and surname.
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