equerry

noun2

1. •
   (UK) A personal attendant to a head of state, a member of a royal family, or a national representative.

   • A bedroom is provided for the equerry and one for the King's physician. […] The compartments for the doctor and equerry are panelled in West African betula and cherry mahogany. — 1947
2. •
   An officer responsible for the care and supervision of the horses of a person of rank.