Definition of "underneath"

connected with it underneath, you see a very fine hair-spring.

1825, Isaac Taylor, Scenes of British Wealth: In Produce, Manufactures, and Commerce, for the Amusement and Instruction of Little Tarry At-home Travellers‎

No insects exhibit, like them, what may be termed four net-work eyes. It is very easy to perceive them in looking at the animal from above, and then examining it underneath

1832, Georges Cuvier, translated by Edward Griffith, edited by Georges Cuvier, Edward Pidgeon, and Edward Griffith, The Animal Kingdom: Arranged in Conformity with Its Organization‎, volume 14, published 2012

The mess in the kitchen was one thing. The way the place smelled was another—some sort of chemistry-lab stink on top, some other smell underneath it. He was afraid the underneath smell might be blood.

1990, Stephen King, The Moving Finger

Nawnim yelped, heaved away, struck his head on the underneath of the bed, and rolled into view bawling.

1938, Xavier Herbert, chapter V, in Capricornia‎, page 64

It was a monolith of a golden color, opening at its base on to a cavern: its underneath was hollowed out by water.

2002, Mary Ann Caws, Surrealist Painters and Poets: An Anthology‎, page 229

I have been looking for an underneath I couldn't see.

2010, Molly Brodak, A Little Middle of the Night‎, page 13

they harden up a little as they cool, and they should be damp within; that's what makes them chewy, so don't worry that the underneaths of the macaroons look sticky.

2011, Nigella Lawson, Nigella Express: Good Food Fast‎

The underneath is music from the latest album by [...].

2009, Jay Trachtenberg (radio host), KUT-FM Radio, Austin, Texas, 17 Dec.