'Bottom' in the Bible

And these are the measures of the altar by cubits (the cubit is a cubit and a handbreadth): the bottom shall be a cubit, and the breadth a cubit, and the border thereof by the edge thereof round about a span; and this shall be the base of the altar.

And from the bottom upon the ground to the lower ledge shall be two cubits, and the breadth one cubit; and from the lesser ledge to the greater ledge shall be four cubits, and the breadth a cubit.

And the ledge shall be fourteen cubits long by fourteen broad in the four sides thereof; and the border about it shall be half a cubit; and the bottom thereof shall be a cubit round about; and the steps thereof shall look toward the east.