See The Peerage

Peer, a member of The Peerage; Landed Gentry - Aristocracy / Aristocracy (class) and related to the term “Peer of the Realm”

Snippet from Wikipedia: Gentleman

A gentleman (Old French: gentilz hom, "gentle man"; colloquial: gent) is a chivalrous, courteous, or honourable man. Originally, gentleman was the lowest rank of the landed gentry of England, ranking below an esquire and above a yeoman; by definition, the rank of gentleman comprised the younger sons of the younger sons of peers, and the younger sons of a baronet, a knight, and an esquire, in perpetual succession. As such, the connotation of the term gentleman captures the common denominator of gentility (and often a coat of arms); a right shared by the peerage and the gentry, the constituent classes of the British nobility.

Thus, the English social category of gentleman corresponds to the French gentilhomme (nobleman), which in Great Britain meant a member of the peerage of England. English historian Maurice Keen further clarifies this point, stating that, in this context, the social category of gentleman is "the nearest contemporary English equivalent of the noblesse of France." In the 14th century, the term gentlemen comprised the hereditary ruling class, which is whom the rebels of the Peasants' Revolt (1381) meant when they repeated:

When Adam delved and Eve span,
Who was then the gentleman?

In the 17th century, in Titles of Honour (1614), the jurist John Selden said that the title gentleman likewise speaks of "our English use of it" as convertible with nobilis (nobility by rank or personal quality) and describes the forms of a man's elevation to the nobility in European monarchies. In the 19th century, James Henry Lawrence explained and discussed the concepts, particulars, and functions of social rank in a monarchy, in the book On the Nobility of the British Gentry, or the Political Ranks and Dignities of the British Empire, Compared with those on the Continent (1827).

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Snippet from Wikipedia: Gentlewoman

A gentlewoman (from the Latin gentilis, belonging to a gens, and English 'woman') in the original and strict sense is a woman of good family, analogous to the Latin generosus and generosa. The closely related English word "gentry" derives from the Old French genterise, gentelise, with much of the meaning of the French noblesse and the German Adel, but without the strict technical requirements of those traditions, such as quarters of nobility.

By association with gentleman, the word can refer to:

• A woman of gentle birth or high social position;
• A woman attending a great lady (as, for example, the character in William Shakespeare's Macbeth called only 'Gentlewoman', who attends Lady Macbeth). This might be a court appointment as the female equivalent to a valet de chambre.
• A woman with good manners and high standards of behaviour.

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