(Also with modifying word and chiefly with possessive adjective) a title of respect or respectful form of address given to a person entitled to be addressed as (Royal, etc.) Highness.
Origin
Late 17th century.
Definition of Highness-ship in US English:
Highness-ship
noun
(Also with modifying word and chiefly with possessive adjective) a title of respect or respectful form of address given to a person entitled to be addressed as (Royal, etc.) Highness.