When people say 'yacht', as a rule, first they imagine a luxurious sailing boat and only after that they remember large motor yachts, say, of Roman Abramovich or a Saudi prince. Some particularly stubborn comrades demand that only sailing ships be called yachts.
But not even every sailboat can be considered a yacht. And what would Wikipedia tell us?
Yacht (Dutch: jacht, from jagen, to chase) - originally a light, fast vessel for the carriage of individual persons, equipped with a deck and cabin(s). In the modern sense - any vessel designed for sports or tourism purposes and recreation. Vessels intended for commercial purposes, for transportation of a large number of passengers (when the main purpose is transport and not recreation and entertainment on board) and other transport purposes do not belong to yachts.
As you can see, there is no clear indication in this definition that the yacht must be only sailing. The main purpose is tourism and recreation. Moreover, very many sailing yachts are not purely sailing yachts. They are power-sail, i.e. there is an engine in the boat which allows to run without wind or maneuvering in tight spaces

So, we've established that yachts can be:
- sailing;
- motor yachts;
- sail-powered.
I do not talk about the first and the last in my blog, because I do not know them much. Under sail, unfortunately, did not go. I hope that this pleasure is yet to come to me, but for now I have what I have. I can not say that I am a big expert and motor yachts. Nevertheless, I know enough about them, the subject is extremely interesting to me, and I am happy to talk about it.
What should be called a motor yacht and what should be called only a boat is a complicated question.
It seems to me that a motorboat, just like a yacht, can have interior rooms, but they are noticeably limited by volume, by comfort. However, perhaps I am wrong. Perhaps it is the size. Or perhaps a boat is a subspecies of a yacht. Certainly, this definition is exclusively within the limits of my blog or yachting subject.
How can we classify yachts? You can read this at https://yapp.pro/