CV = curriculum vitae. Your life's work. It's a catch-all, including ALL of your employment experiences, internships, publications, educational experiences, lectures, projects, languages, leadership experiences, honors, and so on. It can go on for pages and pages. Most of the time when I've seen CVs, they've been of professors (who ideally publish a lot and have been well educated and teach a diverse array of classes / have given public lectures).
Resumes are more targeted, concise documents that are limited to one (Max 2) page(s). When you apply for jobs, you want to present a concise document that showcases the skills and experience you anticipate the employer is looking for, for whichever specific position you are applying to.