Caleb is an attractive Old Testament name that has been in the US Top 100 for nearly three decades now. Consistently popular but never too popular, Caleb feels more like a classic than a momentary trend.

Charles derives from the Germanic name Karl, meaning "man" or "free man", and is a royal name in multiple European countries. A famous early bearer is Charlemagne, King of the Franks and Lombards and then Roman Emperor in the 8th-9th centuries.

Callahan, the simpler spelling of Callaghan, is a rhythmic jig of a name whose history harks back to the ancient King of Munster. In the Dirty Harry movies, the Clint Eastwood character is Harry Callahan.

Callen is a unisex Gaelic name growing in popularity here. Its newfound trendiness is possibly related to the Chris O'Donnell character on "NCIS: Los Angeles", known only as G. Callen. Jazz musician Cal Tjader's full name is Callen.

Caelen is a masculine name of Gaelic origin, considered a variant spelling of Caelan or Kaelan. The name derives from Celtic roots meaning "slender" or "powerful in battle." Some sources also connect it to the Gaelic word for "companion." The spelling with 'ae' creates a distinctive look while maintaining the traditional pronunciation (KAY-len). Caelen began gaining modest popularity in English-speaking countries during the late 20th century as interest in Celtic heritage increased. The name carries associations with strength and grace simultaneously. Caelen offers parents a name with authentic Celtic roots and a contemporary feel, fitting modern naming trends that favor distinctive spellings of traditional names. The name projects a gentle strength that works well across different stages of life.

This short-but-strong name is popular for boys in The Netherlands. While Cass is usually a female name in the U.S., it feels just as right for boys.