形容词
名词
1. 绝对必要的;必不可少的;基本的
Something that is essential is extremely important or absolutely necessary to a particular subject, situation, or activity.
2. 必需品;不可或缺之物
The essentials are the things that are absolutely necessary for the situation you are in or for the task you are doing.
3. 基本的;本质的；根本的
The essential aspects of something are its most basic or important aspects.
4. （某学科的）基础，基本知识
The essentials are the most important principles, ideas, or facts of a particular subject.
1. anything indispensable
e.g. food and shelter are necessities of life
the essentials of the good life
allow farmers to buy their requirements under favorable conditions
a place where the requisites of water fuel and fodder can be obtained