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

Symptoms include angular red, purple, or brown lesions on the upper surfaces of leaves, often between veins, with whitish fungal growth on the undersides. —Rita Perwich, San Diego Union-Tribune, 2 May 2026

While the bridge carries only vehicle traffic, there are tours that allow visitors to traverse the maintenance catwalks on the structure's underside. —Zach Wichter, USA Today, 1 May 2026

The spongy underside of the cap has pores—rather than gills as seen in Agaricales mushrooms such as shiitake and portobello—which are the openings to tubes through which spores exit the mushroom. —Encyclopedia Britannica, 1 May 2026

The left and right rocker buttons located on the undersides of the glasses' temples adjust the audio volume and picture brightness, respectively. —Will Greenwald, PC Magazine, 29 Apr. 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