Ordinal Number

"In linguistics, ordinal numbers are words representing position or rank in a sequential order. The order may be of size, importance, chronology, and so on. In English, they are adjectives such as 'third' and 'tertiary'. They differ from cardinal numbers, which represent quantity."

Spatial/chronological	first	second	third	fourth	fifth	sixth	seventh	eighth	ninth	tenth	eleventh	twelfth
Precedence/effect	primary	secondary	tertiary	quaternary	quinary	senary	septenary	octonary	novenary	decenary	undenary	duodenary
Greek prefix	proto-	deutero-	trito-	tetarto-	pempto-	ecto-	ebdomo-	ogdoo-	enato-	decato-	endecato-	dodecato-

Source: http://en.wikipedia.org/wiki/Ordinal_number_%28linguistics%29