Argh! So I can't create synonyms until I have at least 5 upvotes in that tag, and even then, I can't create a synonym if no-one else has that text on the site? So I can't create colour as a synonym of color (doesn't exist), and I can't create part-id or piece-id as synonyms of identification because I don't have 5 votes in identification (only 3, and on deleted posts) :(