Decimus is a very rare boys' name that peaked in 2006 and has grown less common since.
Decimus is a boy name. In 2025 it ranked #9,109 for boy births in the United States (and #18,839 across all names), given to 8 babies. Decimus was first reported in SSA data in 2006 and peaked in 2006 (8 births).
Boys named Decimus per year · hover for count and boys rank · Source: U.S. Social Security Administration, national data 2006–2025 · U.S.+territories from SSA territory files (1998–2025) · SSA publishes a name only in years it was given to at least 5 babies, so a name may have been in use before — or between — the years shown here