Some people may be confused so here’s an easy answer
There are different axis the board can rotate on.
The main 2 are lengthwise (nose-tail) and through the center of the board (top/bottom) while it’s horizontal.
If it rotates along the nose-tail axis, it’s a flip (flips must rotate 360 to land,not counting casper and dark slide stuff)
If it rotates horizontally, it’s a spin. (This can rotate only 180 and still land)
Then there are blends where the board rotates on both axis at the same time.
Like someone said, there are exceptions, like impossible, where the board flips on its rail-to-rail axis, but as long at the trucks rotate above the board (which usually means the board must rotate 360 to land) it’s a flip.