noun
declaration of ending a state of war
Formal legal or diplomatic term; used in contexts such as peace treaties or official announcements.
両国は戦争状態終結宣言に署名した。
Both countries signed a declaration ending the state of war.
終戦宣言 is a more general 'declaration of the end of a war', while 戦争状態終結宣言 specifically refers to the formal termination of the legal state of war.
Compound of 戦争状態 (state of war) + 終結 (termination) + 宣言 (declaration). A modern legal term.