Husband asked me the other day "what is the difference between a suit jacket, a sports jacket/coat and a blazer? They all seem like the same to me". My fashionably obtuse other half is not the only one unaware of the major differences. He didn't ask about a tuxedo jacket as that one seemed self-explanatory.
Back in the days of the roaring 20's, the distinction between the jacket styles was very important. The secret is in the buttons:
**In the 'old days' a blazer was usually embellished with a badge or patch from a private school or club (social or otherwise). They were generally double breasted (3 buttons in 2 rows), worn with non-matching trousers.
**A sports jacket has 3 or more buttons in the front, with a looser fit than a suit jacket. There are extra pockets, pocket flaps and noticeable stitching details. They are made of more casual materials such as linen or tweeds. They are considered for everyday wear. Elbow patches used to be common features.
These 3 categories have evolved so that today's man seems to look great in one or all 3 types. I love a man in a suit jacket and worn jeans. I also love a man who wears a sports jacket with loose, linen trousers. I say that when a man is confident in himself, he can really wear anything. OK, maybe not socks and sandals! I must draw the line somewhere!