Is a machine WORD always the same or does it depend on the machine architecture?
And is the meaning of the word WORD context sensitive or generally applicable?
All you youngsters yappin' on about 32 bit thiss and 64 bit that: you know, there were and are other machine architectures than the x86 family. A PDP-11 had 40-bit words, f'rinstance.
But the simplest answer is just to search Wikipedia.