研究社新英和大辞典 ページ 197638 での【・from January 1st to 31st inclusive [incl.] 1 月 1 日から 31 日に至るまで 《1 日も 31 日も含めて; cf. 《英》 from January 1st through to January 31st, 《米》 from January 1 throug】単語。