purveyor to the Imperial Household; official supplier
Historical and formal term for a business officially appointed to supply goods or services to the Imperial Household or other high-ranking entities. Now often used loosely in marketing.
popular with a specific clientele; favorite of; go-to for
Informal, often humorous or marketing use. Indicates a place or product that is especially popular with or caters to a particular group, e.g., セレブ御用達 (popular with celebrities).