The terms attorney, attorney at law, and lawyer have become synonymous, and they all refer to being licensed to practice law by some court.[W]hat is an Esquire? Why do some attorneys choose to sign their name as Joe Lawyer, Esq...?
Lawyer refers to your training whereas attorney refers to your ability to practice before a particular jurisdiction.
Esquire is a meaningless title ... now given to anyone willing to subject themselves to law school.
Esquire is a title which has come to be associated with American lawyers (not American law school graduates who are not lawyers).
It is often appropriate to address correspondence to an attorney as "Esq." or "Esquire". However, it is not appropriate for a lawyer to refer to himself or herself as or "Esq." or "Esquire", or to include or "Esq." or "Esquire" on business cards or as part of a signature.