Would someone mind contributing a tag-wiki entry for characters? Unfortunately my own familiarity with them ends at basic representation theory, and I am not familiar enough with Dirichlet characters and their related concepts to capture them also in a short blurb.
(I'm asking because this is one of those cases where mathematicians take a perfectly ordinary English word and spin its meaning; a tag wiki can help point out to users unfamiliar with the concept that "no, this is not the tag you are looking for".)
