This is the 2283rd most frequent Russian word.
исторической
"Исторической" means "historical" in English.
The word 'исторической' (historical) is an adjective modifying 'столицей' (capital), indicating a connection to history.
Петербург является исторической столицей России.
St. Petersburg is the historical capital of Russia.
The word 'исторической' (historical) is used as an adjective modifying 'эпохи' (eras), denoting their significance in history.
Эта книга описывает исторической эпохи нашей страны.
This book describes historical eras of our country.
Here, 'исторической' (historical) modifies 'экспозицией' (exhibit), indicating it showcases historical objects or themes.