adj (1) 重(必)要的，紧要的 (of the greatest importance; absolutely necessary) [A(to/for)] [尤作 pred]：an～part of sth 必要的部分;Food is～to life. 食物对于生命是必不可少的。Books are～to a teacher. 书对于教师来说是必不可少的。Strong boots are～for mountaineering. 登山必须有结实的靴子。Respecting everyone's opinion is～in friendship. 尊重每个人的观点对于友谊是很必要的。The～thing to do is ... 重要的是 ……; It is～to eat regularly for good health/that you practice if you want to be really good. 要想身体好，按时吃饭尤为重要/如果你想真正做好，多练习是至关重要的。〖同〗 necessary，needed，vital; 〖反〗 unimportant，incidental，unnecessary，secondary，minor，trivial;

(2) 本(实)质的，基本的 (of the basic or inner nature of something) [作attrib]：the～theme of a play/purpose of a vocation 剧本的主题/假期的根本目的; the～difference between sth 某些东西之间的本质区别; Her most ～quality is kindness. 她最本质的品德是善良。〖同〗 basic，fundamental，main，key，principal，leading，important，inherent;〖反〗 unimportant，incidental，immaterial，secondary;

n 要点(素)，精华(髓)，本(实)质 (thing that is necessary or very important) [C，常pl]：the～of English grammar 英语语法的基本要素; grasp/outline the～s 抓住/概括要旨;～of life 生活本质; learn the～of sth 学习某事的要点; Is a computer an～? 计算机是必需品吗? Take along only ～s when travelling. 旅行时只带必要的用品。〖同〗requisite，necessity，basics， fundamentals， principles; 〖反〗 accessory，extra，option;

←′essence n 本(实)质;

→e′ssentially adv 实质地，基本地;e′ssentialism n 基本教育论;͵essenti′ality n 本(实)质(性);e′ssentialize v 讲明 …… 的本质