Any of various extinct, often gigantic, carnivorous or herbivorous reptiles of the orders Saurischia and Ornithischia that were chiefly terrestrial and existed during the Mesozoic era.

• 恐龙:一种主要生活在中生代时期的陆栖动物,是庞大的食肉或食草爬行类动物,属龙盘目与鸟盘目,已绝种。