Calix comes from the Latin calix and means "chalice" or "cup"; the related papal name Callixtus derives from the Greek kallistos, "most beautiful". Its sleek X ending places it alongside Felix, Phoenix and Onyx in the current taste for sharp-sounding boys' names. In the United States Calix had fewer than five births in 2000, ranked number 3524 in 2015 and has climbed to number 2010 in 2025, its best rank so far.