underpart
noun
un·der·part ˈən-dər-ˌpärt 
1
: a part lying on the lower side (as of a bird or mammal)
2
: a subordinate or auxiliary part or role
Synonyms
- bottom
- underbelly
- underbody
- underside
- undersurface
See all Synonyms & Antonyms 
Example Sentences
the bird's underparts were white
Recent Examples on the Web Calliope hummers have glossy green on the back and crown with white underparts. 
Joan Morris, The Mercury News, 26 July 2019 The adult brown pelican has gray underparts with brown hues, black-brown belly, yellow head and dark brown neck, silver-gray back and wings, with black feathers at the tips. Ernie Cowan, San Diego Union-Tribune, 13 June 2019
Joan Morris, The Mercury News, 26 July 2019 The adult brown pelican has gray underparts with brown hues, black-brown belly, yellow head and dark brown neck, silver-gray back and wings, with black feathers at the tips. Ernie Cowan, San Diego Union-Tribune, 13 June 2019 Word History
First Known Use
1613, in the meaning defined at sense 1
Kids Definition
underpart
noun
un·der·part ˈən-dər-ˌpärt
: a part lying on the lower side (as of a bird or mammal)
underpart
noun
as in underside
the side or part facing downward from something the bird's underparts were white Synonyms & Similar Words
Relevance
- underside
- bottom
- undersurface
- underbody
- floor
- foot
- toe
- underbelly
- belly
- sole
- seat
- base
- undercarriage
- ground
- underpinning
Antonyms & Near Antonyms
- top
- face
- roof
- apex
- crest
- crown
- height
- tip
- peak
- head
- meridian
- pinnacle
- summit
- climax
- acme
- point
- culmination
- zenith
- high-water mark
- cusp
- tip-top