Synonyms

underside

American

[uhn-der-sahyd] / ˈʌn dərˌsaɪd /

noun

an under or lower side.

underside British

/ ˈʌndəˌsaɪd /

noun

the bottom or lower surface

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of underside

First recorded in 1670–80; under- + side ¹

Vocabulary lists containing underside

Florida's B.E.S.T. Common Prefixes: under-

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Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

They often keep the underside of each slab as it is instead of flattening the bottoms.

From Los Angeles Times • Apr. 8, 2026

Max Beier almost put Dortmund ahead in the first half but his effort was deflected by Denis Vavro's last-ditch block onto the underside of the bar.

From Barron's • Feb. 7, 2026

France legend Zinedine Zidane has a claim for taking the most high-pressure Panenka, in the 2006 World Cup final with his penalty hitting the underside of the crossbar and just crossing the line.

From BBC • Jan. 19, 2026

How familiar too is the fact that his little feet have kicked free of his swaddling, revealing 10 bare toes and the underside of one foot.

From The Wall Street Journal • Dec. 26, 2025

“Haint blue,” Aunt Rose said, pointing to the pale blue painted on the underside of the porch’s overhang.

From "Ophie's Ghosts" by Justina Ireland

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023