What is Uniform ?
Uniform is noun special clothes worn by all members of an organisa- tion or group He went to the fancy dress party dressed in a policeman’s uniform. Who are those people in French army uni- form? What colour is her school uniform? The holiday camp staff all wear yellow uni- forms. in uniform wearing a uniform The policeman was not in uniform at the time. adj all the same, never changing The supermarket wants vegetables of uniform size and colour.
source: Easier English, Student Dictionary Upper Intermediate Level