Sentence:  But up to this time the application of the <WSD>player</WSD> mechanism had been confined to reed instruments, the piano manufacturers having successfully resisted the introduction of the <WSD>player</WSD> mechanism into the piano; but, in the meantime, the manufacturers of <WSD>players</WSD> had grown strong and the manufacturers were beginning to properly interpret the handwriting on the wall 
Meaning of the word marked with <WSD> tags:  A mechanism that actuates a player piano or other automatic musical instrument.