Definition of "underpart" [un•der•part]

• 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. (noun)
• A subordinate role, as in a play. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "And now I saw that there did seem to be a mighty long rock laid across the topmost part of the upstanding rock, and yet had a very strange and shapely appearance; and did seem upon the underpart to be as that I had lookt before upon it."
• "There hung the white phone, held in place and the receiver prevented from falling by a wide U-shaped copper band fastened between two sides of the underpart of the table; near it was fastened a small metal box from which a pair of thin wires ran down the inside of the table leg."
• "The underpart of the pulpit was faced by latticed panels inset between the legs, the whole thing stained and polished to the shade generally known as “a burnished hue.”"