Source : Webster's Revised Unabridged Dictionary (1913)

What \What\, pron., a., & adv. [AS. hw[ae]t, neuter of hw[=a]
   who; akin to OS. hwat what, OFries. hwet, D. & LG. wat, G.
   was, OHG. waz, hwaz, Icel. hvat, Sw. & Dan. hvad, Goth. hwa.
   [root]182. See {Who}.]
   1. As an interrogative pronoun, used in asking questions
      regarding either persons or things; as, what is this? what
      did you say? what poem is this? what child is lost?

            What see'st thou in the ground?       --Shak.

            What is man, that thou art mindful of him? --Ps.
                                                  viii. 4.

            What manner of man is this, that even the winds and
            the sea obey him!                     --Matt. viii.
                                                  27.

   Note: Originally, what, when, where, which, who, why, etc.,
         were interrogatives only, and it is often difficult to
         determine whether they are used as interrogatives or
         relatives. What in this sense, when it refers to
         things, may be used either substantively or
         adjectively; when it refers to persons, it is used only
         adjectively with a noun expressed, who being the
         pronoun used substantively.

   2. As an exclamatory word:
      (a) Used absolutely or independently; -- often with a
          question following. ``What welcome be thou.''
          --Chaucer.

                What, could ye not watch with me one hour?
                                                  --Matt. xxvi.
                                                  40.
      (b) Used adjectively, meaning how remarkable, or how
          great; as, what folly! what eloquence! what courage!

                What a piece of work is man!      --Shak.

                O what a riddle of absurdity!     --Young.

   Note: What in this use has a or an between itself and its
         noun if the qualitative or quantitative importance of
         the object is emphasized.
      (c) Sometimes prefixed to adjectives in an adverbial
          sense, as nearly equivalent to how; as, what happy
          boys!

                What partial judges are our love and hate!
                                                  --Dryden.

   3. As a relative pronoun:
      (a) Used substantively with the antecedent suppressed,
          equivalent to that which, or those [persons] who, or
          those [things] which; -- called a compound relative.

                With joy beyond what victory bestows. --Cowper.

                I'm thinking Captain Lawton will count the noses
                of what are left before they see their
                whaleboats.                       --Cooper.

                What followed was in perfect harmony with this
                beginning.                        --Macaulay.

                I know well . . . how little you will be
                disposed to criticise what comes to you from me.
                                                  --J. H.
                                                  Newman.
      (b) Used adjectively, equivalent to the . . . which; the
          sort or kind of . . . which; rarely, the . . . on, or
          at, which.

                See what natures accompany what colors. --Bacon.

                To restrain what power either the devil or any
                earthly enemy hath to work us woe. --Milton.

                We know what master laid thy keel, What workmen
                wrought thy ribs of steel.        --Longfellow.
      (c) Used adverbially in a sense corresponding to the
          adjectival use; as, he picked what good fruit he saw.

   4. Whatever; whatsoever; what thing soever; -- used
      indefinitely. ``What after so befall.'' --Chaucer.

            Whether it were the shortness of his foresight, the
            strength of his will, . . . or what it was. --Bacon.

   5. Used adverbially, in part; partly; somewhat; -- with a
      following preposition, especially, with, and commonly with
      repetition.

            What for lust [pleasure] and what for lore.
                                                  --Chaucer.

            Thus, what with the war, what with the sweat, what
            with the gallows, and what with poverty, I am custom
            shrunk.                               --Shak.

            The year before he had so used the matter that what
            by force, what by policy, he had taken from the
            Christians above thirty small castles. --Knolles.

   Note: In such phrases as I tell you what, what anticipates
         the following statement, being elliptical for what I
         think, what it is, how it is, etc. ``I tell thee what,
         corporal Bardolph, I could tear her.'' --Shak. Here
         what relates to the last clause, ``I could tear her;''
         this is what I tell you. What not is often used at the
         close of an enumeration of several particulars or
         articles, it being an abbreviated clause, the verb of
         which, being either the same as that of the principal
         clause or a general word, as be, say, mention,
         enumerate, etc., is omitted. ``Men hunt, hawk, and what
         not.'' --Becon. ``Some dead puppy, or log, orwhat
         not.'' --C. Kingsley. ``Battles, tournaments, hunts,
         and what not.'' --De Quincey. Hence, the words are
         often used in a general sense with the force of a
         substantive, equivalent to anything you please, a
         miscellany, a variety, etc. From this arises the name
         whatnot, applied to an ['e]tag[`e]re, as being a piece
         of furniture intended for receiving miscellaneous
         articles of use or ornament.

What \What\, n.
   Something; thing; stuff. [Obs.]

         And gave him for to feed, Such homely what as serves
         the simple ?lown.                        --Spenser.

What \What\, interrog. adv.
   Why? For what purpose? On what account? [Obs.]

         What should I tell the answer of the knight. --Chaucer.

         But what do I stand reckoning upon advantages and gains
         lost by the misrule and turbulency of the prelates?
         What do I pick up so thriftily their scatterings and
         diminishings of the meaner subject?      --Milton.