The Collaborative International Dictionary of English v.0.48:

Transposition \Trans`po*si"tion\, n. [F. transposition, from L.
   transponere, transpositum, to set over, remove, transfer;
   trans across, over + ponere to place. See Position.]
   The act of transposing, or the state of being transposed.
   Specifically:
   [1913 Webster]
   (a) (Alg.) The bringing of any term of an equation from one
       side over to the other without destroying the equation.
       [1913 Webster]
   (b) (Gram.) A change of the natural order of words in a
       sentence; as, the Latin and Greek languages admit
       transposition, without inconvenience, to a much greater
       extent than the English.
       [1913 Webster]
   (c) (Mus.) A change of a composition into another key.
       [1913 Webster]

WordNet (r) 3.0 (2006):

transposition
    n 1: any abnormal position of the organs of the body [syn:
         transposition, heterotaxy]
    2: an event in which one thing is substituted for another; "the
       replacement of lost blood by a transfusion of donor blood"
       [syn: substitution, permutation, transposition,
       replacement, switch]
    3: (genetics) a kind of mutation in which a chromosomal segment
       is transfered to a new position on the same or another
       chromosome
    4: (mathematics) the transfer of a quantity from one side of an
       equation to the other along with a change of sign
    5: (electricity) a rearrangement of the relative positions of
       power lines in order to minimize the effects of mutual
       capacitance and inductance; "he wrote a textbook on the
       electrical effects of transposition"
    6: the act of reversing the order or place of [syn:
       transposition, reversal]
    7: (music) playing in a different key from the key intended;
       moving the pitch of a piece of music upwards or downwards