[ sit-uhp ]

  1. an exercise in which a person lies flat on the back, lifts the torso to a sitting position, and then lies flat again without changing the position of the legs: formerly done with the legs straight but now usually done with the knees bent.

Origin of sit-up

First recorded in 1835–45; noun use of verb phrase sit up

Words Nearby sit-up Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use sit-up in a sentence

  • The hut was barely high enough to let him sit up, and long enough to let him lie down—not to stretch out.

    The Giant of the North | R.M. Ballantyne
  • They had been permitted to sit up till after the ice-cream, which naturally marked the limit of human indulgence.

  • By that time the fellow I'd kicked had so far recovered as to sit up, and the look he gave us was a scorcher.

    Raw Gold | Bertrand W. Sinclair
  • It is not an easy matter to sit up in a gale of wind, with freezing spray, and sometimes green seas, sweeping over one!

  • At dusk he left off, saying he should get it done at night, his senses would come then, and he should be glad to sit up.

    The Daisy Chain | Charlotte Yonge

British Dictionary definitions for sit up

sit up

  1. to raise (oneself or another) from a recumbent to an upright or alert sitting posture

  2. (intr) to remain out of bed and awake, esp until a late hour

  1. (intr) informal to become suddenly interested or alert: devaluation of the dollar made the money market sit up

  1. a physical exercise in which the body is brought into a sitting position from one lying on the back: Also: trunk curl

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

Other Idioms and Phrases with sit-up


Rise to a sitting position from lying down, as in The sick child sat up and asked for a drink of water. [Early 1200s]

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.