Old English giellan (West Saxon), gellan (Mercian) "to yell, sound, shout," III strong verb (past tense geal, past participle gollen), from Proto-Germanic *gel- (source also of Old Norse gjalla "to resound," Middle Dutch ghellen, Dutch gillen, Old High German gellan, German gellen "to yell"), extended form of root of Old English galan "to sing" (source of the -gale in nightingale); from PIE root *ghel- (1) "to call." Intransitive sense from early 13c. Related: Yelled; yelling.