Dame is an honorific title and the feminine form of address for the honour of damehood in many Christian chivalric orders, as well as the British honours system and those of several other Commonwealth realms, such as Australia and New Zealand, with the masculine form of address being Sir. It is the female equivalent of a knighthood, which is traditionally granted to males. Dame is also a style used by baronetesses in their own right.
The Investiture of Dame Lourett Russell Grant into the "Order of The Holy Sepulchre"
Sir is a formal honorific address in English for men, derived from Sire in the High Middle Ages. Both are derived from the old French "Sieur" (Lord), brought to England by the French-speaking Normans, and which now exist in French only as part of "Monsieur", with the equivalent "My Lord" in English. Traditionally, as governed by law and custom, Sir is used for men who are knights and belong to certain orders of chivalry, as well as later applied to baronets and other offices. As the female equivalent for knighthood is damehood, the suo jure female equivalent term is typically Dame. The wife of a knight or baronet tends to be addressed as Lady, although a few exceptions and interchanges of these uses exist.
Sir Thomas Troubridge, 1st Baronet, whose entitlement to use 'Sir' derived from his position as baronet
Emperor Taishō, a Stranger Knight of the Order of the Garter, who, as a foreign national, was not entitled to use the prefix 'Sir' (which as a sovereign monarch he would not have used in any case) but was permitted to post-nominally use KG
Chithira Thirunal Balarama Varma was the last surviving Knight Grand Commander of the Order of the Star of India.
