any

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

• adjective One, some, every, or all without specification.
• adjective Exceeding normal limits, as in size or duration.
• pronoun Any one or more persons, things, or quantities.
• adverb To any degree or extent; at all.

from The Century Dictionary.

• In the singular, one, a or an, some; in the plural, some: indeterminately distributed, implying unlimited choice as to the particular unit, number, or quantity, and hence subordinately as to quality, whichever, of whatever quantity or kind; an indeterminate unit or number of units out of many or all.
• [In affirmative sentences, any, being indeterminate in application, in effect has reference to every unit of the sort mentioned, and thus may be nearly equivalent to every: as, any schoolboy would know that; any attempt to evade the law will be resisted: so in anybody, any one, anything, etc.
• When any is preceded by a negative, expressed or implied, the two are together equivalent to an emphatic negative, ‘none at all,’ ‘not even one’: as, there has never been any doubt about that.
• In the singular, one, some; in the plural, some: indeterminately distributed in the same uses as the adjective, and used absolutely or followed by of in partitive construction: with reference to persons, any one, anybody; in the plural, any persons.
• [In this sense it might formerly have a possessive.
• In any degree; to any extent; at all: especially used with comparatives, as any better, any worse, any more, any less, any sooner, any later, any longer, etc.
• Also, in negative and interrogative sentences, used absolutely: as, it didn't rain any here; did it hurt him any?

from the GNU version of the Collaborative International Dictionary of English.

• adverb To any extent; in any degree; at all.
• adjective One indifferently, out of an indefinite number; one indefinitely, whosoever or whatsoever it may be.
• adjective Some, of whatever kind, quantity, or number; as, are there any witnesses present? are there any other houses like it?
• adjective whatever may be the state of affairs; anyhow.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adverb To even the slightest extent, at all.
• determiner At least one; of at least one kind. One at all.
• determiner No matter what kind.
• pronoun Any thing(s) or person(s).

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• adverb to any degree or extent
• adjective one or some or every or all without specification