'Back part' in the Bible

And kept back part of the price, his wife having knowledge of it, and took the rest and put it at the feet of the Apostles.

But Peter said, Ananias, why has the Evil One put it into your heart to be false to the Holy Spirit, and to keep back part of the price of the land?

And coming to a point between two seas, they got the ship to land; and the front part was fixed in the sand and not able to be moved, but the back part was broken by the force of the waves.