Quote from : It Is Finished: "Tetelestai": The Most Powerful Words Ever Spoken Book

The Greek word that Jesus said on the cross and that we interpret as “It is finished ” is the Greek word tetelestai. Tetelestai comes from the verb teleo, which means to bring to an end, to complete, to accomplish. In the times of Jesus, receipts often had the word tetelestai written on them. This word meant that the receipt or debt was paid in full.