Actually the actual word is buey, which means ox. But people do say it as wey, anyways, it is dude. You use it with your friends, and thats all. Ex Que onda wey? Whats up dude? A wey what are you going to do tomorrow? A dude what are you going to do tomorrow? It is slang thats all, just like vato, wey, carnal ect....