Original meaning of the term
transcription had to do with the taking of
music from one
instrument and re-writing it for another.
It is not uncommon, say, for J.S. Bach to take music written originally for the violin, and transcribe it for clavichord, to be played now on piano.
I have used the term to mean the changing of the medium from a novel to a movie. (I would have expected Webster 1913 to have thought of this.)