ordinal numeral; ordinal number
Linguistics term for words like 'first', 'second', 'third', etc. In Japanese, examples include 第一, 二番目, and 三つ目.
'第一' and '二番目' are examples of ordinal numerals.
Compound of 序 (order) + 数 (number) + 詞 (word/part of speech). A straightforward Sino-Japanese technical term.