Noun

(necessities)

The quality or state of being necessary, unavoidable, or absolutely requisite.

* {{quote-magazine, date=2013-06-28, author=(Joris Luyendijk)

, volume=189, issue=3, page=21, magazine=(The Guardian Weekly) , title= Our banks are out of control , passage=Seeing the British establishment struggle with the financial sector is like watching an alcoholic […].  Until 2008 there was denial over what finance had become. […]  But the scandals kept coming, […]. A broad section of the political class now recognises the need for change but remains unable to see the necessity of a fundamental overhaul.}}

The condition of being needy or necessitous; pressing need; indigence; want.

That which is necessary; a requisite; something indispensable.

*

Love and compassion are necessities , not luxuries. Without them humanity cannot survive.

That which makes an act or an event unavoidable; irresistible force; overruling power; compulsion, physical or moral; fate; fatality.

* 1804 , Wordsworth,

I stopped, and said with inly muttered voice,

'It doth not love the shower, nor seek the cold:

This neither is its courage nor its choice,

But its necessity in being old.

The negation of freedom in voluntary action; the subjection of all phenomena, whether material or spiritual, to inevitable causation; necessitarianism.

(legal) Greater utilitarian good; used in justification of a criminal act .

(legal, in the plural) Indispensable requirements (of life).

Noun

(en noun)

A necessity or prerequisite; something required or obligatory.

Something asked.

(engineering) A statement (in domain specific terms) which specifies a verifiable constraint on an implementation that it shall undeniably meet or (a)'' be deemed unacceptable, or ''(b)'' result in implementation failure, or ''(c) result in system failure.