Coel’s name was rendered “Coil” in Old Welsh. It may be the same as the common noun coel, meaning “belief, credence; confidence, reliance, trust, faith” (a secondary meaning is “omen”), derived from Proto-Celtic *kaylo- “omen” and ultimately from Proto-Indo-European *keh2ilo- “whole, healthy; blessed with good omen”. Coel is often named as “Coel Hen”, Hen being an epithet meaning “old” (i. e. , “Coel the Old”). The genealogies give him an additional epithet, Godebog (Old Welsh: Guotepauc), meaning “Protector” or “Shelterer”. His name is thus sometimes given as “Coel Godebog” or “Coel Hen Godebog”. However, some of the Harleian genealogies list Godebog as Coel’s father’s name. Geoffrey of Monmouth rendered the name as both Coel and Coillus in his Historia Regum Britanniae. Some modern authors modernize it to “Cole”.