Black tie is a semi-formal Western dress code for evening events. Men wear a tuxedo with black bow tie, white dress shirt, and patent leather shoes. Women wear a floor-length gown or sophisticated cocktail dress. Fabric requirements are strict: silk, wool barathea, or velvet for the jacket; no synthetic blends visible. Originated in the 1860s as a less formal alternative to white tie. Climate adaptation matters: lightweight wool or silk-blend tuxedos perform best in tropical venues with air conditioning.