部屋へや代だいへやだいMeanings1nounroom rent; rent for a roomRefers specifically to the cost of renting a room, as opposed to an entire apartment or house.部屋へや代だいは毎まい月つき五ご万まん円えんです。The room rent is 50,000 yen per month.部屋へや代だいを払はらうのを忘わすれていた。I forgot to pay the room rent.