The three get confused often: a suit jacket is made to match its trousers and is the most formal; a sport coat is the most casual, in rugged, textured fabrics like tweed; a blazer sits between, structured and dressy but meant to be worn as a separate.
That versatility — pairs with jeans, trousers, or a skirt — is exactly why a blazer anchors so many smart-casual outfits.
