'Base' in the Bible

At the base of these chambers there was an entryway on the east side as one enters them from the outer court.

“These are the measurements of the altar in units of length (each unit being the standard length plus three inches): the gutter is 21 inches deep and 21 inches wide, with a rim of nine inches around its edge. This is the base of the altar.

There was a stone wall around the inside of them, around the four of them, with ovens built at the base of the walls on all sides.