tri·cer·a·tops / trīˈserəˌtäps/ • n. a large quadrupedal herbivorous dinosaur (genus Triceratops, infraorder Ceratopsia, order Ornithischia) living at the end of the Cretaceous period, having a massive head with two large horns, a smaller horn on the beaked snout, and a bony frill above the neck.

triceratops Large, horned, ornithischian dinosaur of the late Cretaceous period of w North America. The 2.4-m (8-ft) skull carried two 102-cm (40-in) horns above its eyes and a smaller horn at the tip of its snout. Length: 6.1–7.6m (20–25ft); height: 2.4m (8ft); weight: 10 tonnes.