Source : Webster's Revised Unabridged Dictionary (1913)

Exist \Ex*ist"\, v. i. [imp. & p. p. {Existed}; p. pr. & vb. n.
   {Existing}.] [L. existere, exsistere, to step out or forth,
   emerge, appear, exist; ex out + sistere to cause to stand, to
   set, put, place, stand still, fr. stare to stand: cf. F.
   exister. See {Stand}.]
   1. To be as a fact and not as a mode; to have an actual or
      real being, whether material or spiritual.

            Who now, alas! no more is missed Than if he never
            did exist.                            --Swift.

            To conceive the world . . . to have existed from
            eternity.                             --South.

   2. To be manifest in any manner; to continue to be; as, great
      evils existed in his reign.

   3. To live; to have life or the functions of vitality; as,
      men can not exist water, nor fishes on land.

   Syn: See {Be}.

Source : WordNet®

existing
     adj 1: having existence or being or actuality; "an attempt to
            refine the existent machinery to make it more
            efficient"; "much of the beluga caviar existing in the
            world is found in the Soviet Union and Iran" [syn: {existent}]
            [ant: {nonexistent}]
     2: existing in something specified; "depletion of the oxygen
        existing in the bloodstream"
     3: presently existing; "the existing system"