noun which may take the genitive case particle 'no', adverb
historic; historical; in history
Used as a no-adjective or adverb to describe something that exists or happened in history, or is significant from a historical perspective.
これは歴史上の出来事です。
This is a historical event.
歴史上、このようなことは初めてだ。
This is the first time in history that something like this has happened.
Compound of 歴史 (history) + 上 (on, above, in terms of), literally 'on history' or 'in terms of history'.