Highness

Highness is a formal style used to address or refer to certain members of a reigning or formerly reigning dynasty. It is typically used with a possessive adjective: "His Highness", "Her Highness" (HH), "Their Highnesses" (TH), etc. Although often combined with other adjectives of honour indicating rank, such as "Imperial", "Royal" or "Serene", it may be used alone.