'Back part' in the Bible

However, he kept back part of the proceeds with his wife’s knowledge, and brought a portion of it and laid it at the apostles’ feet.

Then Peter said, “Ananias, why has Satan filled your heart to lie to the Holy Spirit and keep back part of the proceeds from the field?

And to keep back part of the price of the land? While it remained, did it not remain thine? And when it was sold, was it not in thy power? Why hast thou conceived this thing in thy heart? Thou hast not lied to men, but to God.

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.