why
Pronunciation: (hwī, wī), [key] — adv., conj., n., pl. interj. whys,
—adv. - for what? for what reason, cause, or purpose?: Why did you behave so badly?
—conj. - for what cause or reason: I don't know why he is leaving.
- for which; on account of which (usually after reason to introduce a relative clause): the reason why he refused to go.
- the reason for which: That is why he returned.
—n. - a question concerning the cause or reason for which something is done, achieved, etc.: a child's unending hows and whys.
- the cause or reason: the whys and wherefores of a troublesome situation.
—interj. - (used as an expression of surprise, hesitation, etc., or sometimes a mere expletive): Why, it's all gone!
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.