What is cocktail attire?

Cocktail attire is a semi-formal dress code that's more elegant than casual wear but less formal than black tie.

For those feeling feminine:

A cocktail dress, jumpsuit, or skirt and blouse. Dresses are usually mid-length, but mini dresses are acceptable too.

For those feeling masuline:

A pair of classic trousers and button up shirt.

Blazer and/or tie optional.

No jeans or t-shirts.