NECESSITY

[noun] - the need for somethingYou can come early and help if you want to, but there's no necessity. [U]Is there any necessity for me to be in the office tomorrow? [U + to infinitive]The report stresses the necessity of eating plenty of fresh fruit and vegetables. [U]With a personal fortune of six million pounds she certainly doesn't work out of necessity (= because she needs to). [U]There's no necessity to pay in advance. [U + to infinitive]We'll employ extra staff to help out as and when the necessity arises (= when we need to). [U]A necessity or bare necessity is something that you need, esp. in order to live.They lack the money even for basic food and heating - the necessities of life.(saying) 'Necessity is the mother of invention' means that if it is very important to you that you do something, you will find a way of doing it, even if it is very difficult.