In the United States, a CV is almost exclusively limited to professions in academia, science and medicine. In the case of academia, the main focus of the CV should be to identify yourself as a scholar. The added length, should be filled with proof of your skills as a teacher, scholar, and your knowledge of education. A CV should be thought of as a living document, and it will change frequently based on the updates in your education and career.
Some companies will indicate that they want you to submit a CV rather than a resume. A CV and a resume are not the same. CV stands for “curriculum vitae” and is meant to be an expansion of your resume. It is much longer than a resume, often three pages or more, and focuses mainly on your academic and professional accomplishments, with a particular focus on education.