Board Thread:General Discussion/@comment-258494-20160113201524

When two or more adjectives modify a noun, before a noun, use a hyphen.

Thus, "18th-oldest person" is correct. "18th oldest person" is not. The second form is confusing and could be taken to mean "18th "oldest-person".Ryoung122 (talk) 20:15, January 13, 2016 (UTC) 