focal length
noun [ C usually singular ] physics specialized uk/ˌfəʊ.kəl ˈleŋθ/ us/ˌfoʊ.kəl ˈleŋθ/
焦距
the distance between a point where waves of light meet and the centre of a lens
英汉双解词典收录81607条英汉双解翻译词条,基本涵盖了全部常用单词的读音、翻译及用法,是英语学习的有利工具。