Source : Webster's Revised Unabridged Dictionary (1913)

Compose \Com*pose"\, v. t. [imp. & p. p. {Composed}; p. pr. &
   vb. n. {Composing}.] [F. composer; com- + poser to place. The
   sense is that of L. componere, but the origin is different.
   See {Pose}, v. t.]
   1. To form by putting together two or more things or parts;
      to put together; to make up; to fashion.

            Zeal ought to be composed of the highest degrees of
            all pious affection.                  --Bp. Sprat.

   2. To form the substance of, or part of the substance of; to
      constitute.

            Their borrowed gold composed The calf in Oreb.
                                                  --Milton.

            A few useful things . . . compose their intellectual
            possessions.                          --I. Watts.

   3. To construct by mental labor; to design and execute, or
      put together, in a manner involving the adaptation of
      forms of expression to ideas, or to the laws of harmony or
      proportion; as, to compose a sentence, a sermon, a
      symphony, or a picture.

            Let me compose Something in verse as well as prose.
                                                  --Pope.

            The genius that composed such works as the
            ``Standard'' and ``Last Supper''.     --B. R.
                                                  Haydon.

   4. To dispose in proper form; to reduce to order; to put in
      proper state or condition; to adjust; to regulate.

            In a peaceful grave my corpse compose. --Dryden.

            How in safety best we may Compose our present evils.
                                                  --Milton.

   5. To free from agitation or disturbance; to tranquilize; to
      soothe; to calm; to quiet.

            Compose thy mind; Nor frauds are here contrived, nor
            force designed.                       --Dryden.

   6. (Print.) To arrange (types) in a composing stick in order
      for printing; to set (type).

Composed \Com*posed"\, a.
   Free from agitation; calm; sedate; quiet; tranquil;
   self-possessed.

         The Mantuan there in sober triumph sate, Composed his
         posture, and his look sedate.            --Pope.
   -- {Com*pos"ed*ly}, adv. -- {Com*pos"ed*ness}, n.

Source : WordNet®

composed
     adj 1: made up of individual elements; "if perception is seen as
            composed of isolated sense data..."
     2: serenely self-possessed and free from agitation especially
        in times of stress; "the performer seemed completely
        composed as she stepped onto the stage"; "I felt calm and
        more composed than I had in a long time" [ant: {discomposed}]