PIE *ghel「輝く、光る」から。語源的にはglass「輝く」と同じ。
Joe Grady and Ed Hurst, WPEN disk jockey team, will be given a gold record by Mercury of the one-millionth copy of Frankie Lane's waxing of That's My Desire, January 10, for having done so much to plug the platter in these parts [Philadelphia]" [Billboard, Jan. 10, 1948]