WordWeb Online

1. The side of an object that is opposite its front
   "his room was toward the backside of the hotel";
   - rear, back end
    
2. The fleshy part of the human body that you sit on
   "he deserves a good kick in the backside";
   - buttocks, nates, butt, bum, buns [N. Amer], can [N. Amer, informal], fundament, hindquarters, hind end, posterior, rear, rear end, rump, stern, seat, tail, tail end, tooshie, tush [N. Amer], bottom, behind, derriere, heinie [US], derrière

Derived forms: backsides

Type of: body part, face, side

Part of: body, torso, trunk

Encyclopedia: Backside