ordinal
noun [ C ] uk/ˈɔː.dɪ.nəl/ us/ˈɔːr.dən.əl/ (also ordinal number)
序数词
a number such as 1st, 2nd, 3rd, 4th, that shows the position of something in a list of things
Fifth and 200th are ordinal numbers. 第五（Fifth）和第二百（200th）都是序数词。
Compare: cardinal noun (NUMBER)