Fourteenth is not the number 14 itself — that word is fourteen. Fourteenth tells you the place in a line: after thirteen others, this one is number 14 in order. We use it for dates (the fourteenth of May), for centuries (the fourteenth century is the years 1300 to 1399), for kings and queens (Louis the Fourteenth), and for anything we put in order (the fourteenth question). You can use it like an adjective (the fourteenth floor) or as a noun when the rest is obvious (“I’ll see you on the fourteenth”). It is an ordinary, neutral word, not fancy and not slang.

第十四；日期則說十四日