A CPA is a Certified Public Accountant: an accountant who has passed a set of hard professional exams and met the other rules of the licence, so they may put those letters after their name. In the United States this is a protected title. It is not just “someone who is good with numbers.” A CPA is the person allowed to do the heavy, trusted work — checking a company’s books, signing an audit, standing behind the figures. People say the letters, C-P-A, not a word. Though actually, the letters are used for other phrases in other jobs; in a money or business setting, this is the meaning. The word is formal and professional. Students sometimes treat every accountant as a CPA; only the ones who have passed, and kept the licence, should use it.