Source : Webster's Revised Unabridged Dictionary (1913)

   Note: In the ancient phrases, all too dear, all too much, all
         so long, etc., this word retains its appropriate sense
         or becomes intensive.

   2. Even; just. (Often a mere intensive adjunct.) [Obs. or
      Poet.]

            All as his straying flock he fed.     --Spenser.

            A damsel lay deploring All on a rock reclined.
                                                  --Gay.

   {All to}, or {All-to}. In such phrases as ``all to rent,''
      ``all to break,'' ``all-to frozen,'' etc., which are of
      frequent occurrence in our old authors, the all and the to
      have commonly been regarded as forming a compound adverb,
      equivalent in meaning to entirely, completely, altogether.
      But the sense of entireness lies wholly in the word all
      (as it does in ``all forlorn,'' and similar expressions),
      and the to properly belongs to the following word, being a
      kind of intensive prefix (orig. meaning asunder and
      answering to the LG. ter-, HG. zer-). It is frequently to
      be met with in old books, used without the all. Thus
      Wyclif says, ``The vail of the temple was to rent:'' and
      of Judas, ``He was hanged and to-burst the middle:'' i.
      e., burst in two, or asunder.

   {All along}. See under {Along}.

   {All and some}, individually and collectively, one and all.
      [Obs.] ``Displeased all and some.'' --Fairfax.

   {All but}.
      (a) Scarcely; not even. [Obs.] --Shak.
      (b) Almost; nearly. ``The fine arts were all but
          proscribed.'' --Macaulay.

   {All hollow}, entirely, completely; as, to beat any one all
      hollow. [Low]

   {All one}, the same thing in effect; that is, wholly the same
      thing.

   {All over}, over the whole extent; thoroughly; wholly; as,
      she is her mother all over. [Colloq.]

   {All the better}, wholly the better; that is, better by the
      whole difference.

   {All the same}, nevertheless. ``There they [certain
      phenomena] remain rooted all the same, whether we
      recognize them or not.'' --J. C. Shairp. ``But Rugby is a
      very nice place all the same.'' --T. Arnold. -- See also
      under {All}, n.

But \But\ (b[u^]t), prep., adv. & conj. [OE. bute, buten, AS.
   b[=u]tan, without, on the outside, except, besides; pref. be-
   + [=u]tan outward, without, fr. [=u]t out. Primarily,
   b[=u]tan, as well as [=u]t, is an adverb. [root]198. See
   {By}, {Out}; cf. {About}.]
   1. Except with; unless with; without. [Obs.]

            So insolent that he could not go but either spurning
            equals or trampling on his inferiors. --Fuller.

            Touch not the cat but a glove.        --Motto of the
                                                  Mackintoshes.

   2. Except; besides; save.

            Who can it be, ye gods! but perjured Lycon? --E.
                                                  Smith.

   Note: In this sense, but is often used with other particles;
         as, but for, without, had it not been for. ``Uncreated
         but for love divine.'' --Young.

   3. Excepting or excluding the fact that; save that; were it
      not that; unless; -- elliptical, for but that.

            And but my noble Moor is true of mind . . . it were
            enough to put him to ill thinking.    --Shak.

   4. Otherwise than that; that not; -- commonly, after a
      negative, with that.

            It cannot be but nature hath some director, of
            infinite power, to guide her in all her ways.
                                                  --Hooker.

            There is no question but the king of Spain will
            reform most of the abuses.            --Addison.

   5. Only; solely; merely.

            Observe but how their own principles combat one
            another.                              --Milton.

            If they kill us, we shall but die.    --2 Kings vii.
                                                  4.

            A formidable man but to his friends.  --Dryden.

   6. On the contrary; on the other hand; only; yet; still;
      however; nevertheless; more; further; -- as connective of
      sentences or clauses of a sentence, in a sense more or
      less exceptive or adversative; as, the House of
      Representatives passed the bill, but the Senate dissented;
      our wants are many, but quite of another kind.

            Now abideth faith hope, charity, these three; but
            the greatest of these is charity.     --1 Cor. xiii.
                                                  13.

            When pride cometh, then cometh shame; but with the
            lowly is wisdom.                      --Prov. xi. 2.

   {All but}. See under {All}.

   {But and if}, but if; an attempt on the part of King James's
      translators of the Bible to express the conjunctive and
      adversative force of the Greek ?.

            But and if that servant say in his heart, My lord
            delayeth his coming; . . . the lord of that servant
            will come in a day when he looketh not for him.
                                                  --Luke xii.
                                                  45, 46.

   {But if}, unless. [Obs.] --Chaucer.

            But this I read, that but if remedy Thou her afford,
            full shortly I her dead shall see.    --Spenser.

   Syn: {But}, {However}, {Still}.

   Usage: These conjunctions mark opposition in passing from one
          thought or topic to another. But marks the opposition
          with a medium degree of strength; as, this is not
          winter, but it is almost as cold; he requested my
          assistance, but I shall not aid him at present.
          However is weaker, and throws the opposition (as it
          were) into the background; as, this is not winter; it
          is, however, almost as cold; he required my
          assistance; at present, however, I shall not afford
          him aid. The plan, however, is still under
          consideration, and may yet be adopted. Still is
          stronger than but, and marks the opposition more
          emphatically; as, your arguments are weighty; still
          they do not convince me. See {Except}, {However}.

   Note: ``The chief error with but is to use it where and is
         enough; an error springing from the tendency to use
         strong words without sufficient occasion.'' --Bain.

Source : WordNet®

all but
     adv : (of actions or states) slightly short of or not quite
           accomplished; `near' is sometimes used informally for
           `nearly' and `most' is sometimes used informally for
           `almost'; "the job is (just) about done"; "the baby was
           almost asleep when the alarm sounded"; "we're almost
           finished"; "the car all but ran her down"; "he nearly
           fainted"; "talked for nigh onto 2 hours"; "the
           recording is well-nigh perfect"; "virtually all the
           parties signed the contract"; "I was near exhausted by
           the run"; "most everyone agrees" [syn: {about}, {just
           about}, {almost}, {most}, {nearly}, {near}, {nigh}, {virtually},
            {well-nigh}]