early 13c., pl. of M.E. galwe "gallows," from O.N. galgi, or from O.E. galga (Mercian), gealga (W. Saxon); all from P.Gmc. *galg- "pole" (cf. O.Fris. galga, M.H.G. galge "gallows, cross"), perhaps cognate with Lith. zalga "pole, perch," Armenian dzalk "pole." Originally also used of the cross of the crucifixion. Plural because made of two poles.