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].
"of or pertaining to the sea off the west coast of Africa," early 15c., Atlantyke, from Latin Atlanticus, from Greek Atlantikos "of Atlas," adjectival form of Atlas (genitive Atlantos), in reference to Mount Atlas in Mauritania (see Atlas). Applied since c. 1600 to the ocean between Europe and Africa, on one side, and the Americas on the other. As a noun late 14c., Athlant, from Old French Atlante.