Old English halgian "to make holy, sanctify; to honor as holy, consecrate, ordain," related to halig "holy," from Proto-Germanic *hailagon (source also of Old Saxon helagon, Middle Dutch heligen, Old Norse helga), from PIE root *kailo- "whole, uninjured, of good omen" (see health). Used in Christian translations to render Latin sanctificare. Related: Hallowed; hallowing.