The Military Origin of Formal Fashion
The sleek, waist-length mess jacket was originally just a tail-less tailcoat designed for convenience. It transitioned from a practical military dining uniform to a stylish choice for tropical formal events.
This jacket evolved from the 18th-century spencer, a garment created by simply chopping the tails off a standard coat. Because it was worn in military mess halls, it became known as a mess jacket. The style later became a sophisticated alternative to heavy formal wear in hot climates during the 1930s. Interestingly, it is also famous as the traditional uniform for young students at Eton College.
Source: Mess jacket