Royal Highness (abbreviation HRH) is a style (His Royal Highness or Her Royal Highness); plural Royal Highnesses (abbreviation TRH, Their Royal Highnesses). It appears in front of the names of some members of some royal families other than the King or Queen. The style His/Her Royal Highness ranks below His/Her Imperial Highness (referring to an Imperial House) but above His/Her Grand Ducal Highness, His/Her Highness, His/Her Serene Highness and some other styles (referring to Grand Ducal, Princely or Ducal Houses).