backside//ˈbæk.saɪd//B1Frequency Level 12ColloquialNounbacksideSingularbacksidesPlural1The buttocks; a person's bottom.He slipped on the ice and landed on his backside.2The rear or back part of something, especially a building or area.The backside of the building has a small garden.SynonymbottomrearbuttocksAntonymfront
