as

Multiple Entries:
  as    AS    As    A    ad-    arsenic    as-  

Concise Oxford English Dictionary © 2008 Oxford University Press:
as1 /az, əz/

▶adverb used in comparisons to refer to the extent or degree of something.

■ used to emphasize an amount.

▶conjunction

• 1 used to indicate simultaneous occurrence.

• 2 used to indicate by comparison the way that something happens.

• 3 because.

• 4 even though.

▶preposition

• 1 used to refer to the function or character of someone or something.

• 2 during the time of being.

– phrases
as for (or to) with regard to.
as from (or of) chiefly Brit. from a particular time or date.
as if (or though) as would be the case if.
as (it) is in the existing circumstances.
as yet until now or that time.

– origin ME: reduced form of OE alswā ‘similarly’ (see also).

usage: Traditionalists hold that it is correct to say he's not as shy as I rather than he's not as shy as me, but the former construction can sound stilted and is now rarely used in normal speech. For more information on this issue, see usage at than.

Concise Oxford English Dictionary © 2008 Oxford University Press:
as2 /as/

▶noun (pl. asses) an ancient Roman copper coin.

– origin L., ‘a unit’.

Concise Oxford English Dictionary © 2008 Oxford University Press:
AS

▶abbreviation Anglo-Saxon.

Concise Oxford English Dictionary © 2008 Oxford University Press:
As

▶symbol the chemical element arsenic.

Concise Oxford English Dictionary © 2008 Oxford University Press:
A1 (also a)

▶noun (pl. As or A's)

• 1 the first letter of the alphabet.

• 2 denoting the first, best, or most important in a set.

• 3 Music the sixth note of the diatonic scale of C major, having a standard frequency of 440 Hz.

• 4 the human blood type (in the ABO system) containing the A antigen and lacking the B.

– phrases
from A to B from one's starting point to one's destination.
from A to Z over the entire range.

Concise Oxford English Dictionary © 2008 Oxford University Press:
A2

▶abbreviation

• 1 (in card games) ace.

• 2 (in showing goals or points conceded) against.

• 3 ampere(s).

• 4 (Å) ångström(s).

• 5 answer.

• 6 (in names of sports clubs) Athletic.

• 7 attack (in designations of US aircraft types): an A-10.

• 8 Austria (international vehicle registration).

Concise Oxford English Dictionary © 2008 Oxford University Press:
ad- /ad/ (also a- before sc, sp, st; ac- before c, k, q; af- before f; ag- before g; al- before l; an- before n; ap- before p; ar- before r; as- before s; at- before t)

▶prefix

• 1 denoting motion or direction to: advance.

• 2 denoting reduction or change into: adulterate.

• 3 denoting addition or increase: adjunct.

– origin from L. ad ‘to’.

Concise Oxford English Dictionary © 2008 Oxford University Press:
arsenic /ˈɑːs(ə)nɪk/

▶noun the chemical element of atomic number 33, a brittle steel-grey semimetal with many highly poisonous compounds. (Symbol: As)

– derivatives
arsenical adjective.

– origin ME (in sense ‘orpiment’): via OFr. from L. arsenicum, from Gk arsenikon, from Arab. al-zarnīḵ.

Concise Oxford English Dictionary © 2008 Oxford University Press:
as-/as/

▶prefix variant spelling of ad- assimilated before s (as in assemble).