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"
a conflict of opposed ideas or attitudes or goals; "a collision of interests"
an accident resulting from violent impact of a moving object; "three passengers were killed in the collision"; "the collision of the two ships resulted in a serious oil spill"
(physics) an brief event in which two or more bodies come together; "the collision of the particles resulted in an exchange of energy and a change of direction"