This document is an excerpt from the EUR-Lex website
The EU's 'acquis' is the body of common rights and obligations that are binding on all EU countries, as EU Members. It is constantly evolving and comprises:
Applicant countries are required to accept the acquis before they can join the EU. Derogations from the acquis are granted only in exceptional circumstances and are limited in scope. The acquis must be incorporated by applicant countries into their national legal order by the date of their accession to the EU and they are obliged to apply it from that date.