I have no idea what the official definition is. Here is what I think of when I see "pilothouse."
1) An area that is mostly dedicated to helming. Big spaces for all the instruments, charts, and what-have-you, with no attempt to conceal them (since it's not the "living room").
2) There are places for people in addition to the helmsperson to sit facing forward with a good view.
3) Maybe a lazy bench and a watch berth, in a larger pilothouse.
4) Doors to the sidedecks, preferably on both sides.
5) Lots of windows with good visibility (although windows facing aft might be a bit smaller, they are there).
6) Usually somewhat raised in relation to the saloon.
An easy example of a pilothouse to visualize would be a Nordic Tug.
You asked about other types. There are so many: "convertibles," "sundecks," "sportfishes," "motoryachts," "double (tri) cabins," and more. I won't drone on, so will just mention one other type (because I like it), which is the "sedan."
Sedan says to me that the saloon is on the main level, with no other "indoor" living space above it (there may be a flybridge up above though). There is usually a cockpit aft, and that is basically on the same level as the saloon and more or less at water level. The helm (only or lower) is in a forward corner of the saloon. Galley may be up or down.
Think of something like a Grand Banks 32, or a Europa 36 or 42 (which is the layout of a sedan but with covered sidedecks).