单词	focal ratio
释义	focal ratio noun : f-number Example Sentences Recent Examples on the Web An eyepiece changes the focal ratio of your telescope, thus changing the magnification. Cameron Johnson, Popular Mechanics, 10 Nov. 2020 Word History First Known Use 1883, in the meaning defined above
随便看	thencest thener thenest thenner thenness thennest thenoic acid thenoyl thens thenyl theo theo- theobromae theobromas theobromata theobromine theobromines theocentric theocentricisms theocentricities theocentricity theocentrism theocentrisms theocracies theocracy

英语词典包含469781条英英释义在线翻译词条，基本涵盖了全部常用单词的英英翻译及用法，是英语学习的有利工具。