c. 1300, plural of Middle English galwe "gallows" (mid-13c.), from Old Norse galgi "gallows," or from Old English galga (Mercian), gealga (West Saxon) "gallows;" all from Proto-Germanic *galgon "pole" (source also of Old Frisian galga, Old Saxon galgo, Middle High German galge "gallows, cross," German Galgen "gallows," Gothic galga "cross"), from PIE *ghalgh- "branch, rod" (source also of Lithuanian žalga "pole, perch," Armenian dzalk "pole").
In Old English, also used of the cross of the crucifixion. Plural because made of two poles. Gallows-tree is Old English galg-treow. Gallows humor (1876) translates German Galgenhumor.
also cleché, 1680s, "pierced through with a figure of the same kind," but also, of a cross, "having arms which spread or grow broader toward the extremities," from French cléché (17c.), from Latin *clavicatus "key-holed," or clavicella "little key," from clavis "key" (from PIE root *klau- "hook"). The cross sense perhaps from or merged with Latin clava "club, knotty branch."
Middle English rode, "a cross; a crucifix," especially a large one, from Old English rod "cross," especially that upon which Christ suffered, from Proto-Germanic *rod- (source also of Old Saxon ruoda "stake, pile, cross," Old Norse roða, Old Frisian rode, Middle Dutch roede, Old High German ruota, German Rute "rod, pole"), which is of uncertain origin. Perhaps it shares a PIE root with Latin ratis "raft," retae "trees standing on the bank of a stream;" Old Church Slavonic ratiste "spear, staff;" Lithuanian reklės "scaffolding," but de Vaan is doubtful. Probably not connected with rod.
Also in Old English "a pole;" and in Middle English also a local measure varying from 6 to 8 yards and a square measure of land.
word-forming element meaning "across, beyond, through, on the other side of, to go beyond," from Latin trans (prep.) "across, over, beyond," perhaps originally present participle of a verb *trare-, meaning "to cross," from PIE *tra-, variant of root *tere- (2) "cross over, pass through, overcome." In chemical use indicating "a compound in which two characteristic groups are situated on opposite sides of an axis of a molecule" [Flood].