The Collaborative International Dictionary of English v.0.48:

Midst \Midst\, n. [From middest, in the middest, for older in
   middes, where -s is adverbial (orig. forming a genitive), or
   still older a midde, a midden, on midden. See Mid, and cf.
   Amidst.]
   [1913 Webster]
   1. The interior or central part or place; the middle; -- used
      chiefly in the objective case after in; as, in the midst
      of the forest.
      [1913 Webster]

            And when the devil had thrown him in the midst, he
            came out of him.                      --Luke iv. 35.
      [1913 Webster]

            There is nothing . . . in the midst [of the play]
            which might not have been placed in the beginning.
                                                  --Dryden.
      [1913 Webster]

   2. Hence, figuratively, the condition of being surrounded or
      beset; the press; the burden; as, in the midst of official
      duties; in the midst of secular affairs.
      [1913 Webster]

   Note: The expressions in our midst, in their midst, etc., are
         avoided by some good writers, the forms in the midst of
         us, in the midst of them, etc., being preferred.
         [1913 Webster]

   Syn: Midst, Middle.

   Usage: Midst in present usage commonly denotes a part or
          place surrounded on enveloped by or among other parts
          or objects (see Amidst); while middle is used of the
          center of length, or surface, or of a solid, etc. We
          say in the midst of a thicket; in the middle of a
          line, or the middle of a room; in the midst of
          darkness; in the middle of the night.
          [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Midst \Midst\, prep.
   In the midst of; amidst. --Shak.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Midst \Midst\, adv.
   In the middle. [R.] --Milton.
   [1913 Webster]

WordNet (r) 3.0 (2006):

midst
    n 1: the location of something surrounded by other things; "in
         the midst of the crowd" [syn: midst, thick]