What does Esquire mean? And who may use the designation? Esquire has a British origin and has a connotation that generally indicates a man of some sort of distinction. In times past it was the rank below a knight. Today in Britain it is used by all sorts of men for a rainbow of reasons.
Usage in the UK: “The breadth of Esquire (as Esq.) had become universal in the United Kingdom by the late 20th century, for example being applied by some banks to all men who did not have a grander title. Although the College of Arms continues to restrict use of the word Esquire in official grants of arms to a limited set (smaller even than that outlined by the list above), it uses the term Esquire without restriction in addressing correspondence. Many people in the United Kingdom no longer perceive any distinction between “Mr” and “Esquire” at all so that, in everyday usage, a distinction is very rarely intended. To be used with the name in initial format (e.g., K.S. Smith, Esq.) it is still used by many offices of the Chairman in business and also many traditional carriage trade businesses such as Christie’s and Berry Bros. & Rudd. This rather old-fashioned usage is generally employed to imply that the addressee would be of the gentry by the mere fact of the sender’s interaction when addressing those without another, higher, rank or title. British men invited to Buckingham Palace receive their invitations in an envelope with the suffix Esq. after their names while men of foreign nationalities instead have the prefix Mr (women are addressed as Miss, Ms, or Mrs). The same practice applies for other post from the palace (e.g., to employees etc.).”
Usage in the US: “In the United States, the suffix Esq. is most commonly encountered among individuals licensed to practice law. This usage applies to both male and female lawyers. The term was assumed by the legal profession, and not granted to it by any governmental authority.” […lots more on Wikipedia]