Definition of Bolero: A short cropped jacket ending above or at the waist and worn open. Most boleros do not have a collar or lapels.
Vintage boleros from the 1930s to the early 1950s.
So what exactly is a bolero? Usually when one thinks of a bolero visions of a Spanish matador come into mind, which is correct as the bolero jacket was derived from this fashion. (At least to the best of our knowledge!) To keep it simple, just remember that a bolero never has closures. If it does then it's a cropped jacket, not a bolero.