underpart

[ uhn-der-pahrt ]
/ ˈʌn dərˌpɑrt /

noun

the lower part or side: The underpart of the plane's fuselage scraped the treetops.
an auxiliary or secondary part or role.

Origin of underpart

First recorded in 1655–65; under- + part
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

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