Arlen might be thought of as an update on the midcentury Arlene or as a unisex surname-name. Arlen was given to 22 girls in the US last year vs 57 boys and those numbers may grow with the fashion for n-ending two-syllable surname-names. Another similar possibility for girls: Arden.

Arlen is a surname long used as a first name: It ranked on the US Top 1000 from the late 1920s until the late 1960s. Originally, Arlen was a variation of Harlan which came from Harland, a place-name which means "hare land" – a place with lots of rabbits. The name today is occasionally used for both genders, boys twice as often as girls. That may increase with the fashion for two-syllable n-ending boys' names.