Crocodile Show, Million Years Stone Park, Pattaya, Thailand

The word crocodile comes from the Ancient Greek κροκόδιλος (crocodilos), "lizard," used in the phrase ho crocodilos ho potamós, "the lizard of the (Nile) river."
There are several variant Greek forms of the word attested, including the later form κροκόδειλος (crocodeilos) found cited in many English reference works. In the Koine Greek of Roman times, crocodilos and crocodeilos would have been articulated identically, and either or both may be the source of the Latinized form crocodīlus used by the ancient Romans.
Crocodilos/crocodeilos itself is described in reference sources as a corruption of crocè ("pebbly"), and drilos/dreilos supposedly meaning "worm" although attested only as "(man with circumcised) penis". It is unclear how well supported this analysis is. The meaning of crocè is explained as describing the skin texture of lizards (or crocodiles) in most sources, but is alternately claimed to refer to a supposed habit of (lizards or crocodiles) basking on pebbly ground.
The form crocodrillus is attested in Medieval Latin. It is not clear whether this is a medieval corruption or derives from alternate Greco-Latin forms (late Greek corcodrillos and corcodrillion are attested).