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

For an extra special touch, place colorful, shredded tissue paper in the base of the jar and attach a small gift tag to the underside of the jar lid with twine and tape. —Lauren Landers, The Spruce, 31 Jan. 2026

An Italian Tricolore flag on the underside of the pop-up rear spoiler is the finishing touch. —Tim Pitt, Robb Report, 28 Jan. 2026

No, not at it straight-on, but looked at the underside of the faucet, where the water actually flows out. —Stephanie Osmanski, Better Homes & Gardens, 27 Jan. 2026

Meanwhile ice can accrete on both the top and underside of branches and power lines. —Andrea Thompson, Scientific American, 26 Jan. 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