The order issued by the government of Japan
in New Tokyo-2
in episode 25' "Air
". This order means the "abolishment of special legal protection for NERV and transfer of all command to the government of Japan".
" was issued when attempting to capture the Eighth Angel
, so all "A-" orders are thought to be emergency
actions related to NERV
Source: The End of Evangelion : Glossary contained within The End of Evangelion - Theatrical Program.