The Oxford English Dictionary is the most exhaustive, obsessive dictionary in the universe. Further evidence: The OED is soliciting the assistance of science-fiction fans, writers, historians and critics in an effort to compile an dictionary of science-fictional coinages, including etymological and historical notes, as well as exhaustive citations from the literature. This project is so grandiose, it boggles me: SF writers and fans love neologisms and have so many coinages that it's easy to imagine this project filling a volume as thick as an L. Ron Hubbard space-opera. On the other hand, this is just the sort of project that the Internet is very good at.
There are several different things we're looking for here. An antedating is a word that is earlier than the earliest example we currently know. Most words will be in this category. An interdating is a word that fills a (large) gap in the record–if we had an example from 1928 and then nothing until 1995, we'd probably want something in between to show that the word had been in use in this period. A postdating is a word that is later than the latest example we have; if we are looking for one, it is probably because we believe that a word is still current but we don't have an example in any recent decade. Finally, any evidence means just that: we know that a word exists, but we have little or no direct evidence for it. In this case we really do want anything, but it's best to provide examples from important sources, and early examples (or information about coinage/early uses) are always welcome.
