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	tom fool's knot Tom o'Bedlam tom o'bedlams tom safety valve Tom show Tom Thumb Tom Thumbs tom tid Tom Tiddler's ground Tom Tram tom walker tom walkers Tom' tom, dick, and har Tom, Dick, and Harry tom-tom Toma tomahawk tomahawked tomahawking tomahawks tomalley tomalleys toman tomans

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。