fundament
[noun]
Synonyms: buttocks, backside, beam, behind, bottom, derriere, posterior, rear, rump, seat

[TahlilGaran] English Synonym Dictionary ▲

fundament noun. ['fʌndǝm(ǝ)nt] ME.
[Old & mod. French fondement from Latin fundamentum, from fundare FOUND verb¹: see -MENT.]
1. The foundation or base of a wall, building, etc. Also, the action of founding a building, institution, etc.; the building itself. ME-L17.

2. The ground, basis, or principle on which anything is founded. ME-L17.

3. The buttocks, the anus. ME.

4. Geography. The landscape as it appeared before humans began to modify it by their activities. E20.

[TahlilGaran] English Dictionary ▲