Esquire

Alternative meaning: Esquire Magazine

Esquire or Esq. for short was originally a title for the sons of nobles etc., who did not possess any other title. However, today the term is used instead of Mr. on official documents, etc. It is linked to the word squire which is a knight's servant. There is no female equivalent.

From the public domain 1913 Webster's Dictionary:

Es*quire" (?), n. [OF. escuyer, escuier, properly, a shield-bearer, F. �cuyer shield-bearer, armor-bearer, squire of a knight, esquire, equerry, rider, horseman, LL. scutarius shield-bearer, fr. L. scutum shield, akin to Gr. skin, hide, from a root meaning to cover; prob. akin to E. hide to cover. See Hide to cover, and cf. Equerry, Escutcheon.] Originally, a shield-bearer or armor-bearer, an attendant on a knight; in modern times, a title of dignity next in degree below knight and above gentleman; also, a title of office and courtesy; -- often shortened to squire.

In England, the title of esquire belongs to:

the eldest sons of knights and their eldest sons in perpetual succession
the eldest sons of younger sons of peers and their eldest sons in perpetual succession
those who bear special office in the royal household
Sheriffs while in office
Justices of the Peace while in commission
Commissioners of the Court of Bankruptcy
Masters of the Supreme Court
Deputy Lieutenants and Commissioners of Lieutenancy
Queen's Counsel
sergeants at law
Royal Academecians
officers of the Royal Navy with rank of Lieutenant or higher, of the Army with rank of Captain or higher, or of the Royal Air Force with rank of Flight Lieutenant or higher
bachelors of divinity, law, or physics, and others
persons to whom the title is granted by the monarch

Its use (as Esq.) became pervasive in the late 20th century, for example being applied by banks to all men who did not have a grander title.

In the United States the title is commonly given in courtesy to lawyers and justices of the peace, and is often used in the superscription of letters instead of Mr., for example "William Clinton, Esq."

Historically in England, barristers-at-law used this title, while solicitors used the term "gentleman". In the United States, where the roles of counsel and attorney were combined, the term "esquire" was adopted. There is some largely academic controversy over title of "esquire" and how it relates to the The missing thirteenth amendment of America's constitution.

The name Esquire also was used by the Fender Electric Instrument Company as a name for one of its electric guitar models.