Formal wear
Formal wear or formal dress was a term used to describe clothing worn on formal occasions.

In 2365, Geordi La Forge guessed that the Klingon Rite of Ascension would have everyone dressed in formal wear. ()

In 2376, Kathryn Janeway expressed surprise at Lyndsay Ballard's choice of attire when they were having dinner together, as it wasn't necessary. Ballard explained that she chose to dress formally because she was eating with the captain. ()

See also 
 Uniform

External link 
 
Fashion