Serene Highness

Serene Highness is a style used to address or refer to some members of royal families.

When used as a direct form of address, spoken or written, it takes the form Your Serene Highness. When used as a third-person reference, it is gender-specific (His Serene Highness or Her Serene Highness, both abbreviated HSH) and, in plural, Their Serene Highnesses (TSH).