This term is used when referring to traditional animation. It also applies to computer vector animations, where traditional methods are used.
For vector animation. Use the same methods as for the traditional.
Why did I render separately 2D from the traditional one, because there is an opportunity not to draw the whole character frame by frame. But only modify individual parts of the animation. This is a plus of vector animation, because the process is accelerated, but the principles of the animation itself remain the same.
Programs: Adobe after effect, Adobe flash toon boom, tv paint, etc.