Natiform
The Century Dictionary and Cyclopedia
Like or likened to buttocks, as the umbones of a shell: as, the
natiform
tubercles of the brain.
Wiktionary, Creative Commons Attribution/Share-Alike License
adjective.
Resembling
or having the
form
of
buttocks
.
Word Usage
"I may stroke my natiform chin sceptically at Shea's cachinnations, but if such things truly make him tripudiate"