Animation is performance over time. A character, a logo, a product or a diagram moves because someone decided the timing. It can be 2D or 3D, drawn or keyed.
Visual effects are the craft of changing a photographed or rendered shot: adding, removing, extending, matching. A CG character inside a live plate is both. The animation is the performance. The VFX is the integration.
Most people meet both words in film and advertising, which is why the courses overlap. If you like acting with a graph editor or a drawing, start in animation. If you like making a shot believable, start in editing and compositing. Pepper Animation runs both, and the diploma programmes let you cross the hallway once you know which side you care about.