A genus of gigantic herbivorous dinosaurs having a birdlike pelvis and large hind legs with three-toed feet capable of supporting the entire body. Its teeth resemble those of the iguana, whence its name. Several species are known, mostly from the Wealden of England and Europe. See Illustration in Appendix. [1913 Webster]

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OXFORD DICTIONARY

iguanodon, n. a large extinct plant-eating dinosaur of the genus Iguanodon, with forelimbs smaller than hind limbs.

Etymology

IGUANA (from its resemblance to this), after mastodon etc.

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