'Back part' in the Bible

And he measured the length of the building at the face of the separated place which was upon its back part, and its offsets from hence, and from thence, a hundred cubits, and the inner temple and the porches of the enclosure.

And he was upon the back part of the ship, sleeping upon a pillow: and they aroused him, and say to him, Teacher, carest thou not that we perish?