thousandth 2022.12.06 thousandthとは 意味・定義・例文 n, adj, adv 1. 1000th in numbering order 1000番目 the thousandth time 2. the 100th person or thing 1000番目の人[もの] This is the 1000th longest river in the world. 3. one of 1000 equal parts of something; one thousandth(1/1000) A milligram is one-thousandth of a gram.