how

from The American Heritage® Dictionary of the English Language, 5th Edition.

• adverb In what manner or way; by what means.
• adverb In what state or condition.
• adverb To what extent, amount, or degree.
• adverb For what reason or purpose; why.
• adverb With what meaning.
• adverb By what name.
• adverb By what measure; in what units.
• adverb What. Usually used in requesting that something be said again.
• adverb Used as an intensive.
• conjunction The manner or way in which.
• conjunction That.
• conjunction In whatever way or manner; however.
• noun A manner or method of doing something.
• idiom (and how) Most certainly; you bet.
• idiom (how about) Used to make a suggestion or to offer something.
• idiom (how about) Used to request an opinion about something considered remarkable or impressive.
• idiom (how about that) Used rhetorically to express surprise or wonder at or approval for something.
• idiom (how come) How is it that; why.
• idiom (how so) How is it so.

from The Century Dictionary.

• noun The manner of doing or becoming; way.
• To care.
• noun A low hill: obsolete or dialectal, but retained in some place-names: as, Silver How, near Grasmere; Fox How.
• Careful.
• noun Care; anxiety.
• noun A Scotch form of houve.
• Hollow; deep or low.
• noun Any hollow place.
• noun The hold of a ship.
• noun A glen; a dell; also, a plain.
• A syllable of salutation among various tribes of American Indians.
• A. interrogative. In what way? in what manner?
• By what means?—as, how did he do it? how did you come?
• To what degree or extent? in what proportion or amount? by what measure or quantity?—qualifying an adverb or adjective of degree or quantity: as, how large was it? how far did you go? how many tickets did you get?
• In this use often exclamatory in form and affirmative in meaning.
• Such sentences also take in modern speech the affirmative form: as, how much better you are looking! how little you have changed! how stupid he is!
• In what state, condition, or plight?
• So colloquially, in reference to one's health or affairs: as, how do you do? how have you been? how's your family? he asked how you all were; how is business?
• At what price?—as, how do you sell your potatoes? how is wheat going now?
• For what reason ? why?
• To what effect? what? — with regard to a thing said or asked about, as when one asks an opinion or a repetition of a thing said and not understood: equivalent to the simple what?—as, how say you, gentlemen of the jury? How used alone, instead of what, is chiefly colloquial.
• With this use of how is connected its interjectional use, marking surprise, or being a mere greeting or call.
• In this use often with now: as, how now! what are you doing?
• B. relative. In what way; in what manner; the way or manner in which …: introducing a relative clause and performing the office of a conjunctional adverb.
• By what means; the means by which.
• To what degree or extent; in what proportion or amount; by what measure or quantity: qualifying an adverb or adjective: as, I do not know how large it is; I asked him how far he had traveled.
• In what state, condition, or plight.
• At what price: as, he inquired how the stocks were selling.
• For what reason; why.
• That: with reference to the manner, and also to the result: in objective clauses, after say, tell, relate, report, etc.
• Especially in combination: How that, that.