Difference between need and want

Definitions from http://dictionary.reference.com/

Need
–noun
1. a requirement, necessary duty, or obligation: There is no need for you to go there.
2. a lack of something wanted or deemed necessary: to fulfill the needs of the assignment.
3. urgent want, as of something requisite: He has no need of your charity.
4. necessity arising from the circumstances of a situation or case: There is no need to worry.
5. a situation or time of difficulty; exigency: to help a friend in need; to be a friend in need.
6. a condition marked by the lack of something requisite: the need for leadership.
7. destitution; extreme poverty: The family's need is acute.

Want
–noun
11. something wanted or needed; necessity: My wants are few.
12. something desired, demanded, or required: a person of childish, capricious wants.
13. absence or deficiency of something desirable or requisite; lack: plants dying for want of rain.
14. the state of being without something desired or needed; need: to be in want of an assistant.
15. the state of being without the necessaries of life; destitution; poverty: a country where want is virtually unknown.
16. a sense of lack or need of something: to feel a vague want.

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