What's the difference between animation and transition?

Answer 1

Transition - it is changing state.

It might changes for some time(transition-duration)
Used on buttons, to create effects(hover/click) wich ANIMATES properties transition between their 2 states

So in animation there ARE transitions between each key-frame

Answer 2

Transitions and animations are pretty similar except that in transitions you just specify the change in style and the browser specifies how the element should be animated itself whereas in animation we can specify multiple keyframes and the browser animates it according to the key frames