Uniform

uniform 

A stylized set of clothes worn for work, a set method of dress to identify company workers or students at a school.

uniform 

The same, everything being alike or even. "The color of the fresh painted wall is very uniform".

Now the porn version...

In the porn world, uniforms are turned from an item of oppression (polyester!) to a thing of fantasy. Many people have fond memories of the girl that worked at McDonalds or at the airline, and as a result, there are often fantasy / fetish sets built around well known uniform sets. In Japan, their porn industry has taken this to a whole other level, as many Japanese companies have recognizable uniforms that can be used. Many bukkake sites specialize on guys dumping as much cum as possible on a girl dressed like the office girl at the work or whatever.

The most common uniform fetishes are cheerleaders and schoolgirl uniforms.