underside

noun

un·​der·​side ˈən-dər-ˌsīd 

ˌən-dər-ˈsīd

1

: the side or surface lying underneath

2

: a side usually hidden from sight

specifically : the more unpleasant or reprehensible side

the underside of politics

Synonyms of underside

• bottom

Examples of underside in a Sentence

the underside of the table

The book explores the underside of human nature.

Recent Examples on the Web

On many of the planes, the boom operator works lying face down while looking out of a window on the underside of the plane. —Kim Tong-Hyung, Los Angeles Times, 13 Mar. 2026

Dust attracts and harbors pests, so dust the top and underside of the plant's leaves every month with a damp cloth. —Karen Brewer Grossman, Southern Living, 13 Mar. 2026

After the dog zeroed in on the underside of the SUV, the driver was detained, and the vehicle was taken to a secondary screening area. —Alex Riggins, San Diego Union-Tribune, 7 Mar. 2026

The underside of the bridge is rusting and deteriorating. —Chris Hoffman, CBS News, 6 Mar. 2026

Word History

First Known Use

1660, in the meaning defined at sense 1

Rhymes for underside

• actinide
• aldehyde
• alkoxide
• alongside
• amplified
• arsenide
• beautified
• biocide
• butoxide
• calcified
• ceramide
• certified

Kids Definition

underside

noun

un·​der·​side ˈən-dər-ˌsīd 

ˌən-dər-ˈsīd

: the side or part lying underneath