In the United States, esquire (often shortened to Esq.) is a title of courtesy, given to a lawyer and commonly appended to his/her surname (e.g., John Smith, Esq. or John Smith, Esquire) when addressing the lawyer in written form. Note that it is traditionally considered a solecism to append Esq. or Esquire to one’s own name.
In England, esquire does not carry the same professional meaning but is instead a mostly obsolete courtesy title, appended to a man’s name when he has no other title. Historically, the title was an honorific used for a member of the English gentry whose rank was superior to that of a gentleman but inferior to that of a knight.
[Last updated in June of 2021 by the Wex Definitions Team]