It refers to the **seventh rank**.

Torre, who was clearly worse a few moves earlier, profits from Lasker's mistake (22...h6?! 23...Qd5?) by setting a powerful windmill (25.Bf6!!) that allows his rook to wreck havoc on the 7th rank (any rook's promised land): White wins two pawns and a bishop, refrains from snatching a7 in order not to activate the black rook on a8, and then goes back to pick the queen.

Although I had never seen that famous game called *The Seventh Seal* before (rather : *The Windmill Immortal*), its fate was undoubtely sealed on the seventh rank !