What is Cerapoda?

Cerapoda is a combination of Ceratopsia (horned faces) and Ornithopoda (bird feet) so literally means "horned feet". Unfortunately, non of its members have horned feet, but they are on common ground because of their enamelled teeth.

Cerapoda also includes the pachycephalosaurs, affectionately known as "head-bangers", so maybe it should have been called Pachycerapoda "thick-horned-feet", or properly Marginocerapoda "fringe-horned-feet" (as the pachycephalosaurs and ceratopsians together form a cerapodan group known as Marginocephalia, the "fringe heads"). Granted, neither name improves on the original but either would eliminate possible linguistic confusion: if you say Ceropoda really fast it sounds suspiciously like Sauropoda which is a completely different kettle of dinosaurs.

Paul Sereno coined Cerapoda a full year after Cooper had coined Neornithischia, and for all intents and purposes the two groups contained exactly the same members, which resulted in a mild case of "handbags at dawn" between certain palaeontologists with regards to naming priorities and whatnot. However, Neornithischia has been expanded and now houses Cerapoda plus a small handful of non-cerapodan neornithischians, so it all worked out in the end.