necessity

英[nɪ'sesɪtɪ] 美[nə'sɛsəti]

1. the condition of being essential or indispensable

2. anything indispensable;

"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"