What is the difference between a suit jacket and a suit blazer?

The difference between a suit jacket and a suit blazer comes down to formality. Blazers tend to be more casual, and when sold with a pair of trousers, they may be in a different color or material than their companion pieces. You can also style them with khakis and even jeans. Suit jackets are more formal and nearly always feature the same fabric as their matching trousers. On 1stDibs, find an assortment of blazers and suit jackets.