Meaning of PRIMER in English

PRIMER

[noun] [U]Primer is a type of paint that you put on a wooden surface before putting on the main paint.He recommended we should use aluminium primer on bare wood.It's best to use a coat of primer before the top coat.(dated) A primer is also a small book containing basic facts about a subject, used esp. when you are beginning to learn about that subject.This little book could be useful as an examination primer.

Cambridge English vocab.      Кембриджский английский словарь.