UNDERPART
underpart
(noun) a part lying on the lower side or underneath an animal’s body; “the warbler has a white throat and underparts”; “a woodland mouse with white underparts”
Source: WordNet® 3.1
Etymology
Verb
underpart (third-person singular simple present underparts, present participle underparting, simple past and past participle underparted)
(transitive) To divide (a part) and assign subordinate portions of it.
Noun
underpart (plural underparts)
A lower or underneath part
Anagrams
• perdurant
Source: Wiktionary
Un"der*part`, n.
Definition: A subordinate part.
It should be lightened with underparts of mirth. Dryden.
Source: Webster’s Unabridged Dictionary 1913 Edition