Other forms: blazers
A blazer is a jacket that is not as formal as a suit coat, but more formal than a cardigan. If you specify a business casual dress code on your party invitation, many people will show up wearing blazers.
Another name for a blazer is a sports jacket or sport coat. Traditionally, blazers are made of wool or linen. While they come in various colors, a navy blazer is classic. This item of clothing is considered to be a little bit dressy, but not formal like a suit, tuxedo, or evening gown. The word blazer was originally used in colloquial American English for "attention-attracting thing." In late 19th-century British university slang, it came to mean "bright red flannel jacket."