underpart

un·der·part  (ndr-pärt)

n.

1. A lower part or a portion of a lower part or underside, especially of an animal's body: We recognized the robin by its reddish underparts.

2. A subordinate role, as in a play.

Thesaurus

Noun

1.

underpart - 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" belly - the underpart of the body of certain vertebrates such as snakes or fish body part - any part of an organism such as an organ or extremity