Twentieth
来自Big Physics
wiktionary
From Middle English twentithe, twentiþe, from Old English twēntigoþa. Equivalent to twenty + -eth.
etymonline
twentieth (adj., n.)
"next in order after the nineteenth; an ordinal numeral; being one of twenty equal parts into which a whole is regarded as divided;" 16c., from twenty + -th (1), replacing Middle English twentithe, from Old English twentigoða. The Twentieth Century Limited was an express train from New York to Chicago 1902-1967.
