Noah Webster's Dictionary 1. (n.) Foundation. 2. (n.) The part of the body on which one sits; the buttocks; specifically (Anat.), the anus.

Multi-Version Concordance Fundament (1 Occurrence) Judges 3:22 and the haft also goeth in after the blade, and the fat shutteth on the blade, that he hath not drawn the sword out of his belly, and it goeth out at the fundament. (YLT)