Old English glomung "twilight, the fall of evening," found but once (glossing Latin crepusculum), and formed (probably on model of æfning "evening") from glom "twilight," which is related to glowan "to glow" (hence "glow of sunrise or sunset"), from Proto-Germanic *glo- (see glow, v.). Fell from currency except in Yorkshire dialect, but preserved in Scotland and reintroduced by Burns and other Scottish writers after 1785.