Old French and Old Norse name, from roi (king) in French or from the Gaelic Ruadh (red); the single-syllable directness made it a mid-century English staple that is now quietly cycling back.
Vibe
playful
How it ages.
Peaked in mid-century English-speaking countries; currently in gentle revival in the Netherlands and UK.
The cultural moment.
Top 50 in the UK and US from the 1920s through the 1950s; declining until the 2010s when it began a quiet revival in the Netherlands and UK.