Service dress
Service dress is a style of military uniform that is the equivalent of a business suit, i.e. not the very most formal but not informal either.
In the United States Navy, for example, service dress uniforms are worn for official functions not rising to the level of full or dinner dress. They are also commonly worn when traveling in official capacity, or when reporting to a command. They are seasonal, with a white uniform worn in summer and a blue version in winter. The Service Dress Blue may be worn year round for travel only. The civilian equivalent is a business suit.