as

American Heritage® Dictionary of the English Language, Fourth Edition

1. adv. To the same extent or degree; equally: The child sang as sweetly as a nightingale.
2. adv. For instance: large carnivores, as the bear or lion.
3. adv. When taken into consideration in a specified relation or form: this definition as distinguished from the second one.
4. conj. To the same degree or quantity that. Often used as a correlative after so or as: You are as sweet as sugar. The situation is not so bad as you suggest.
5. conj. In the same manner or way that: Think as I think.
6. conj. At the same time that; while: slipped on the ice as I ran home.
7. conj. For the reason that; because: went to bed early, as I was exhausted.
8. conj. With the result that: He was so foolish as to lie.
9. conj. Though: Great as the author was, he proved a bad model. Ridiculous as it seems, the tale is true.
10. conj. In accordance with which or with the way in which: The hotel is quite comfortable as such establishments go. The sun is hot, as everyone knows.
11. conj. Informal That: I don't know as I can answer your question.
12. pro. That; which; who. Used after same or such: I received the same grade as you did.
13. pro. Chiefly Upper Southern U.S. Who, whom, which, or that: Those as want to can come with me.
14. prep. In the role, capacity, or function of: acting as a mediator.
15. prep. In a manner similar to; the same as: On this issue they thought as one.
16. idiom. as is Informal Just the way it is, with no changes or modifications: bought the samovar as is from an antique dealer.
17. idiom. as it were In a manner of speaking; as if such were so.
18. n. An ancient Roman coin of copper or copper alloy.
19. n. An ancient Roman unit of weight equal to about one troy pound.

Century Dictionary and Cyclopedia

1. The antecedent in the correlation as … so, or as … as: In that degree; to that extent; so far. The correlation as … so is obsolete; as … as is in extremely common use, being, besides like, the regular formula of comparison to express likeness or equality: as, as black as jet, as cold as ice, as wise as Solomon, etc.; the verb in the relative clause, when the same as in the principal clause, being usually omitted: as, it is as cold as ice (sc. is); come as soon as you can (sc. come).
2. The relative clause is often omitted, especially in colloquial speech, being inferred from the antecedent: as, this will do as well (sc. as that); I would as lief walk (sc. as ride).
3. The consequent in the correlations as … as, so … as, such … as, same … as, etc., expressing quantity, degree, proportion, manner, etc. The relative uses are as exhibited in I. (where see examples). Through ellipsis of the antecedent, it enters into many peculiar idiomatic phrases.
4. The antecedent as is often, and so is usually, omitted: as, black as jet; cold as ice; do as you like.
5. In parenthetical clauses involving a concession, the relative as (the antecedent being omitted) may be equivalent to though: as, late as it was, we set forth on our journey.
6. In parenthetical clauses involving a contrast or negation as to fact with the principal clause, as approaches an adversative sense, being nearly equivalent to but.
7. In subordinate clauses involving a supposition, as is conditional, being equivalent to as if, as though, which are the ordinary forms. This use is now rare or only poetical except in the independent phrase as it were. (See phrases below.)
8. The clause introduced by as may be reduced by ellipsis of its verb and other elements to one or two important words, leaving as as a quasi-connective: Between an adverb or adverbial phrase in the principal clause and an adverb or adverbial phrase constituting the subordinate clause.
9. Between the principal verb or its subject and the subordinate subject or object, which becomes equivalent to a predicate appositive or factitive object after the principal verb, as meaning ‘after the manner of,’ ‘the same as,’ ‘like,’ ‘in the character or capacity of,’ etc.: as, the audience rose as one man; all these things were as nothing to him; he has been nominated as a candidate. Hence in constructions where the appositive clause depends directly upon the noun: as, his career as a soldier was brilliant; his reputation as a scholar stands high: and so in naming phases of a general subject: as, Washington as a general; man as a thinker. The construction as a quasi-predicate appositive or factitive object after a principal verb is usual after verbs of seeming or regarding.
10. The subordinate clause introduced by as is often not dependent grammatically upon the principal verb, but serves to restrict or determine the scope of the statement as a whole. Such clauses are parenthetical, and usually elliptical, some of them, as as usual and as a rule, having almost the idiomatical unity of an adverbial phrase.
11. In certain emphatic formulas, as (‘even as’) introduces a solemn attestation (‘as truly or surely as’) or adjuration (‘in a manner befitting the fact that’), approaching a causal sense, ‘since, because.’ (See 2, below.)
12. Of reason: Since; because; inasmuch as.
13. Of time: When; while; during the time that.
14. Of purpose or result: The consequent in the correlations so … as, such … as: To such a degree that; in such a manner that: followed by an infinitive or, formerly, by a finite verb (but in the latter construction that has taken the place of as).
15. Of mere continuation, introducing a clause in explanation or amplification of a word or statement in the principal clause, especially in giving examples: For example; for instance; to wit; thus.
16. In dependent clauses: That. Formerly as was often attached, like that, to the adverbs there, then, where, when, etc., to make them distinctly relative. These forms are now obsolete, except whereas, which remains in a deflected sense. See whereas. From this interchange with that followed the use of as for that, in introducing an object clause after say, know, think, etc., varying with as that and as how: only in dialectal use: as, I don't know as I do', and I don't know as' I do, the sense varying with the accent.
17. After comparatives: Than.
18. Before certain adverbs and adverbial phrases, including prepositional phrases: Even; just: restricting the application to a particular point: as, as now, as then, as yet, as here, as there, etc.
19. Before prepositional phrases as becomes attached in thought to the preposition, making practically a new prepositional unit. See as anent, as concerning, as for, etc., below.
20. That; who; which: after such or same, and introducing an attributive clause: as, he did not look for such a result as that; he traveled the same route as I did.
21. An obsolete and dialectal or colloquial form of has: in colloquial speech often further reduced to 's: as, who's been here?
22. n. In Norse myth., one of the gods, the inhabitants of Asgard. See Asgard.
23. n. In Latin, an integer; a whole or single thing; especially, a unit divided into twelve parts. Thus, the jugerum was called an as.
24. n. As a unit of weight, 12 ounces (Latin unciœ, twelfths); the libra or pound, equal to 325.8 grams, or 5,023 grains.
25. n. A copper coin, the unit of the early monetary system of Rome. It was first coined in the fourth (according to Mommsen, the fifth) century b. c., and was at first nominally of the weight of a libra or pound, that is, 12 ounces. It was gradually reduced in weight, about 269 b. c. weighing 4 ounces, and about 250 b. c. 2 ounces. In 80 b. c., after having fallen to half an ounce, it ceased to be issued. The smaller copper coins forming the divisions of the as were named semis (half of the as), triens (third), quadrans (fourth), sextans (sixth), and uncia (twelfth). The constant obverse type of the as has the double head of Janus; the reverse, a prow. Its subdivisions bore various devices. Coins struck on the same system (called the libral system) were issued in other parts of Italy from the fourth century b. c. See œs grave, under œs.
26. n. . Obsolete form of ace. Chaucer.
27. n. An old Swedish and Dutch unit of weight, equal to 4.8042 centigrams, or about three quarters of a troy grain. See asducat and ass.
28. n. Chemical symbol of arsenic.
29. n. An assimilated form of ad- before s, as in assimilate, assert, assume, etc.
30. n. An erroneously restored form of a-, originally Latin ab-, in assoil, assoilzie, from the Latin absolvere, absolve.
31. n. A variant of es-, Latin ex-, in assart, assay, astonish, obsolete ascape, aschew, assaumple, etc.; now represented also, or only, by es-, as in escape, eschew, or s-, as in scape, sample. See es.

Wiktionary

1. n. metrology Symbol for the attosecond, an SI unit of time equal to 10−18 seconds.
2. n. metrology arcsecond
3. adv. To such an extent or degree.
4. adv. In the manner or role specified.
5. adv. dated For example.
6. conj. In the same way that; according to what.
7. conj. At the same instant that; when.
8. conj. At the same time that; while.
9. conj. Varying through time in the same proportion that.
10. conj. Considering that, because, since.
11. conj. Introducing a basis of comparison, after as, so, or a comparison of equality.
12. prep. Introducing a basis of comparison, with an object in the objective case.
13. prep. In the role of.
14. n. unit of weight A libra.
15. n. Any of several coins of Rome, coined in bronze or later copper; or the equivalent value.

GNU Webster's 1913

1. adv. Denoting equality or likeness in kind, degree, or manner; like; similar to; in the same manner with or in which; in accordance with; in proportion to; to the extent or degree in which or to which; equally; no less than
2. adv. In the idea, character, or condition of, -- limiting the view to certain attributes or relations
3. adv. While; during or at the same time that; when.
4. adv. Because; since; it being the case that.
5. adv. Expressing concession. (Often approaching though in meaning).
6. adv. obsolete That, introducing or expressing a result or consequence, after the correlatives so and such.
7. adv. Obs. or Poetic As if; as though.
8. adv. For instance; by way of example; thus; -- used to introduce illustrative phrases, sentences, or citations.
9. adv. Obs. & R. Than.
10. adv. obsolete Expressing a wish.
11. n. obsolete An ace.
12. n. (Chem.) the chemical symbol for arsenic.
13. n. A Roman weight, answering to the libra or pound, equal to nearly eleven ounces Troy weight. It was divided into twelve ounces.
14. n. A Roman copper coin, originally of a pound weight (12 oz.); but reduced, after the first Punic war, to two ounces; in the second Punic war, to one ounce; and afterwards to half an ounce.

WordNet 3.0

1. adv. to the same degree (often followed by `as')
2. n. a very poisonous metallic element that has three allotropic forms; arsenic and arsenic compounds are used as herbicides and insecticides and various alloys; found in arsenopyrite and orpiment and realgar
3. n. a United States territory on the eastern part of the island of Samoa