Meaning

noun having the back covered with thick bony plates; thought to have walked with a sprawling gait resembling a lizard's

originFrom taxonomic name Ankylosaurus, from ankylo- + -saurus, from Ancient Greek ἀγκύλος (ankúlos, “crooked”) + New Latin -saurus, from Ancient Greek σαῦρος (saûros, “lizard”). The word was coined in 1908 without explanation by Barnum Brown and may refer to his mistaken belief that its back was sharply bent in a manner similar to the stegosaurus or to his attention to the fusion of his specimens'…

Etymology from Wiktionary, CC BY-SA 3.0