1. the posterior part of a human (or animal) body from the neck to the end of the spine - his back was nicely tanned • Syn: back • Derivationally related forms: dorsal • Hypernyms: body part • Part Holonyms: torso, trunk, body • Part Meronyms: saddle, small, latissimus dorsi, lat, thoracic vertebra, dorsal vertebra, lumbar vertebra 2. the back of the body of a vertebrate or any analogous surface (as the upper or outer surface of an organ or appendage or part) - the dorsum of the foot • Derivationally related forms: dorsal • Hypernyms: body part