Other forms: dress codes
The rules about what clothing you can and cannot wear are a dress code. Your school's dress code might prohibit students from wearing hats or tank tops.
School dress codes can be controversial, seen as restricting students' freedom of self-expression or applied in a discriminatory or sexist way. Some school dress codes mandate wearing a uniform, while others specify shorts or skirts of certain lengths or prohibit controversial "statement" t-shirts. A fancy restaurant's dress code might require men to wear jackets and ties. And the dress code for your little sister's tea party might include feather boas and sparkly tiaras.