The Collaborative International Dictionary of English v.0.48:

Transpose \Trans*pose"\, v. t. [imp. & p. p. Transposed; p.
   pr. & vb. n. Transposing.] [F. transposer; pref. trans- (L.
   trans across) + poser to put. See Pose.]
   [1913 Webster]
   1. To change the place or order of; to substitute one for the
      other of; to exchange, in respect of position; as, to
      transpose letters, words, or propositions.
      [1913 Webster]

   2. To change; to transform; to invert. [R.]
      [1913 Webster]

            Things base and vile, holding no quantity,
            Love can transpose to form and dignity. --Shak.
      [1913 Webster]

   3. (Alg.) To bring, as any term of an equation, from one side
      over to the other, without destroying the equation; thus,
      if a + b = c, and we make a = c - b, then b is said to be
      transposed.
      [1913 Webster]

   4. (Gram.) To change the natural order of, as words.
      [1913 Webster]

   5. (Mus.) To change the key of.
      [1913 Webster]

WordNet (r) 3.0 (2006):

transpose
    n 1: a matrix formed by interchanging the rows and columns of a
         given matrix
    v 1: change the order or arrangement of; "Dyslexics often
         transpose letters in a word" [syn: permute, commute,
         transpose]
    2: transfer from one place or period to another; "The ancient
       Greek story was transplanted into Modern America" [syn:
       transfer, transpose, transplant]
    3: cause to change places; "interchange this screw for one of a
       smaller size" [syn: counterchange, transpose,
       interchange]
    4: transfer a quantity from one side of an equation to the other
       side reversing its sign, in order to maintain equality
    5: put (a piece of music) into another key
    6: exchange positions without a change in value; "These
       operators commute with each other" [syn: commute,
       transpose]
    7: change key; "Can you transpose this fugue into G major?"