What does "transposition" mean?

Transposition: The act of transposing, or the state of being transposed. Specifically: --(a) (Alg.) The bringing of any term of an equation from one side over to the other without destroying the equation. (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. (c) (Mus.) A change of a composition into another key.