CV is short for curriculum vitae, a document listing someone's education, qualifications and work experience, which they write when looking for a job. In American English, it's called a resume.
The cover letter should not reiterate your resume or curriculum vitae because you've already put that piece of the library together, that piece of the wardrobe.
Dozens of people every day scour the Situations Vacant columns of the press, send off their curriculum vitae or application form, and wait hopefully to be summoned for an interview.