I don't really want to become an editor of Wiktionary, as I mainly work in Wikipedia, but I thought I'd tell you that this term is not generally used as an "uncountable" noun. It is, moreover, a completely illogical term in both singular and plural forms, in spite of its popularity in the U.S. That popularity is based on political bias to entrench further the 2-party system. In Wikipedia I have added:
(The term, while widely used in the U.S., is illogical, as it wrongly implies that several parties are tied for third place.)
- Korky Day, Vancouver, BC, Canada.
- For a noun to be countable means that a numerical counter may be used ahead of the noun. One does not say, "There were five third parties." There can only ever be one "third party" in a discussion. Additional parties become the fourth, fifth, etc. So, the noun is not countable, and actually carries instead some properties of a proper noun. --EncycloPetey 23:06, 12 September 2008 (UTC)