sailor suit; middy uniform
Refers to the classic sailor-style outfit, originally naval-inspired, now iconic as a Japanese school uniform for girls.
She went to school wearing a sailor suit.
sailor-style school uniform; two-piece school uniform
Specifically the two-piece school uniform with a sailor collar, commonly worn by Japanese middle and high school girls.
This school's sailor uniform is navy blue.
She wears her sailor uniform to school every morning.
Girls in sailor uniforms were walking in front of the station.