necessity
/nɪˈsesətɪ/noun
(pl. -ies)
1
- mass noun the fact of being necessary必要（性）。
1.1
necessity of/for/to do something
the fact of being required or indispensable需要; 必要; 不可或缺：the necessity for law and order.
法律和秩序的必要性。
1.2
- unavoidability必然性：
the necessity of growing old.
衰老的必然性。
1.3
- a state of things or circumstances enforcing a certain course强制性, 强迫性：
created more by necessity than design.
多因不得已而创作, 而非计划如此。
2
- an indispensable thing必需品：
a good book is a necessity when travelling.
出门旅行时, 一本好书是必不可少的。
3
- mass noun Philosophy the principle according to which something must be so, by virtue either of logic or of natural law【哲】必然性。
3.1
- count noun a condition that cannot be otherwise, or a statement asserting this必然情况; 断言。
短语
necessity is the mother of invention
- proverb when the need for something becomes imperative, you are forced to find ways of getting or achieving it.〈谚〉需要乃发明之母。
of necessity
- unavoidably势必, 必定, 不可避免地。
词源
late Middle English; from Old French necessite, from Latin necessitas, from necesse 'needful'.