What does Felix mean?
The Latin word felix, “happy” or “lucky.”
What does Rex mean?
Directly from the Latin noun 'rex', meaning 'king' — the same root behind 'regal' and 'royal'. One of the few names that literally means 'king' with no ambiguity.
Felix vs Rex
Which is more popular?
Felix is more popular than Rex today: about 2,064 US babies were given the name Felix in 2025, compared with 281 named Rex.
| Felix | Rex | |
|---|---|---|
| Meaning | Happy, fortunate | king |
| Origin | Latin | latin |
| Gender | Boy | Boy |
| Pronunciation | FEE-liks | reks |
| Syllables | 2 | 1 |
| First appeared | 1880 | 1880 |
| Peak year | 2024 (2,090) | 1951 (1,503) |
| In 2025 | 2,064 | 281 |
| Trend | Near its peak | Steady |
Popularity over time, 1880–2025
Felix
Rex
Source: US Social Security Administration.
Births by decade
| Decade | Felix | Rex |
|---|---|---|
| 2020s | 11,654 | 2,106 |
| 2010s | 13,335 | 3,945 |
| 2000s | 7,580 | 2,048 |
| 1990s | 6,294 | 1,740 |
| 1980s | 5,306 | 2,532 |
| 1970s | 5,515 | 3,359 |
| 1960s | 5,749 | 8,735 |
| 1950s | 5,759 | 13,499 |
| 1940s | 4,315 | 6,671 |
| 1930s | 4,199 | 5,949 |
| 1920s | 6,000 | 5,627 |
| 1910s | 4,928 | 3,253 |
| 1900s | 1,108 | 497 |
| 1890s | 903 | 305 |
| 1880s | 863 | 183 |
Frequently asked questions
Is Felix or Rex more popular?
Felix is more popular than Rex today: about 2,064 US babies were given the name Felix in 2025, compared with 281 named Rex.
What is the difference between Felix and Rex?
Felix means Happy, fortunate (Latin origin), while Rex means king (latin origin).
Which name is older, Felix or Rex?
In US records, Felix first appears in 1880 and Rex in 1880, so Felix has the longer recorded history.