ceterus

Ceterus, cetera, ceterum declines like bonus, but the masculine nominative singular is effectively a ghost: you meet the word in the plural, ceteri, and in the neuter singular. Later scribes routinely wrote caeteri with the diphthong, and both spellings sit in the corpus, so search for either.

Two spin-offs earn their place. The neuter ceterum works as an adverb meaning "but, however, for the rest", and it opens sentences in historians constantly. And et cetera is simply "and the remaining things" - neuter plural, which is why the abbreviation is never "etc." followed by a person. Keep it apart from its neighbours: reliquus is what is left over after some is gone, alius is a different one from a whole field, alter is the other of exactly two, and ceterus is everybody else once you have named the ones you care about.