相あいあいJLPTN1Meanings1prefixtogether; mutually; fellowPrefix used to indicate joint, mutual, or shared action or relationship. Common in compounds like 相部屋 (sharing a room) or 相乗り (riding together).彼かれとは相部屋あいべやになった。I ended up sharing a room with him.相あい乗のりでタクシーに乗のる。We share a taxi.