There are three major differences between CVs and resumes are the length, the purpose and the layout.
A resume is a brief summary of your skills and experience over one or two pages, a CV is more detailed and can stretch well beyond two pages. The resume will be tailored to each position whereas the CV will stay put and any changes will be in the cover letter.
A CV has a clear chronological order listing the whole career of the individual whereas a resume’s information can be shuffled around to best suit the applicant.
I would say the main difference between a resume and a CV is that a CV is intended to be a full record of your career history and a resume is a brief, targeted list of skills and achievements.
CV – long, covers your entire career, static
Resume – short, no particular format rule, highly customisable