Alternate 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. écuyer 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

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.

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.