See more synonyms for sit-up on
  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


verb (used without object), sat or (Archaic) sate; sat or (Archaic) sit·ten; sit·ting.
  1. to rest with the body supported by the buttocks or thighs; be seated.
  2. to be located or situated: The house sits well up on the slope.
  3. to rest or lie (usually followed by on or upon): An aura of greatness sits easily upon him.
  4. to place oneself in position for an artist, photographer, etc.; pose: to sit for a portrait.
  5. to remain quiet or inactive: They let the matter sit.
  6. (of a bird) to perch or roost.
  7. (of a hen) to cover eggs to hatch them; brood.
  8. to fit, rest, or hang, as a garment: The jacket sits well on your shoulders.
  9. to occupy a place or have a seat in an official assembly or in an official capacity, as a legislator, judge, or bishop.
  10. to be convened or in session, as an assembly.
  11. to act as a baby-sitter.
  12. (of wind) to blow from the indicated direction: The wind sits in the west tonight.
  13. to be accepted or considered in the way indicated: Something about his looks just didn't sit right with me.
  14. Informal. to be acceptable to the stomach: Something I ate for breakfast didn't sit too well.
  15. Chiefly British. to take a test or examination: I’m studying now, and I plan to sit in June.
verb (used with object), sat or (Archaic) sate; sat or (Archaic) sit·ten; sit·ting.
  1. to cause to sit; seat (often followed by down): Sit yourself down. He sat me near him.
  2. to sit astride or keep one's seat on (a horse or other animal): She sits her horse gracefully.
  3. to provide seating accommodations or seating room for; seat: Our dining-room table only sits six people.
  4. Informal. to serve as baby-sitter for: A neighbor can sit the children while you go out.
  5. Chiefly British. to take (a test or examination): She finally received permission to sit the exam at a later date.
Verb Phrases
  1. sit down,
    1. to take a seat.
    2. to descend to a sitting position; alight.
    3. to take up a position, as to encamp or besiege: The military forces sat down at the approaches to the city.
  2. sit in,
    1. to attend or take part as a visitor or temporary participant: to sit in at a bridge game; to sit in for the band's regular pianist.
    2. to take part in a sit-in.
  3. sit in on, to be a spectator, observer, or visitor at: to sit in on classes.
  4. sit on/upon,
    1. to inquire into or deliberate over: A coroner's jury was called to sit on the case.
    2. suppress; silence: They sat on the bad news as long as they could.
    3. check or rebuke; squelch: I'll sit on him if he tries to interrupt me.
  5. sit out,
    1. to stay to the end of: Though bored, we sat out the play.
    2. to surpass in endurance: He sat out his tormentors.
    3. to keep one's seat during (a dance, competition, etc.); fail to participate in: We sat out all the Latin-American numbers.
  6. sit up,
    1. to rise from a supine to a sitting position.
    2. to delay the hour of retiring beyond the usual time.
    3. to sit upright; hold oneself erect.
    4. become interested or astonished: We all sat up when the holiday was announced.
  1. sit on one's hands,
    1. to fail to applaud.
    2. to fail to take appropriate action.
  2. sit pretty, Informal. to be in a comfortable situation: He's been sitting pretty ever since he got that new job.
  3. sit tight, to bide one's time; take no action: I'm going to sit tight till I hear from you.

Origin of sit

before 900; Middle English sitten, Old English sittan; cognate with Dutch zitten, German sitzen, Old Norse sitja; akin to Gothic sitan, Latin sedēre, Greek hézesthai (base hed-); cf. set, sedate, cathedral, nest
Can be confusedset sit (see usage note at set)

Synonyms for sit

See more synonyms for on

Usage note

See set. Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for sit up

sit up

verb (adverb)
  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
  3. (intr) informal to become suddenly interested or alertdevaluation of the dollar made the money market sit up
noun sit-up
  1. a physical exercise in which the body is brought into a sitting position from one lying on the backAlso: trunk curl


abbreviation for
  1. stay in touch


verb sits, sitting or sat (mainly intr)
  1. (also tr; when intr, often foll by down, in, or on) to adopt or rest in a posture in which the body is supported on the buttocks and thighs and the torso is more or less uprightto sit on a chair; sit a horse
  2. (tr) to cause to adopt such a posture
  3. (of an animal) to adopt or rest in a posture with the hindquarters lowered to the ground
  4. (of a bird) to perch or roost
  5. (of a hen or other bird) to cover eggs to hatch them; brood
  6. to be situated or located
  7. (of the wind) to blow from the direction specified
  8. to adopt and maintain a posture for one's portrait to be painted, etc
  9. to occupy or be entitled to a seat in some official capacity, as a judge, elected representative, etc
  10. (of a deliberative body) to be convened or in session
  11. to remain inactive or unusedhis car sat in the garage for a year
  12. to rest or lie as specifiedthe nut was sitting so awkwardly that he couldn't turn it
  13. (of a garment) to fit or hang as specifiedthat dress sits well on you
  14. to weigh, rest, or lie as specifiedgreatness sits easily on him
  15. (tr) mainly British to take (an examination)he's sitting his bar finals
  16. (usually foll by for) mainly British to be a candidate (for a qualification)he's sitting for a BA
  17. (intr; in combination) to look after a specified person or thing for someone elsegranny-sit
  18. (tr) to have seating capacity for
  19. sitting pretty informal well placed or established financially, socially, etc
  20. sit tight
    1. to wait patiently; bide one's time
    2. to maintain one's position, stand, or opinion firmly

Word Origin for sit

Old English sittan; related to Old Norse sitja, Gothic sitan, Old High German sizzen, Latin sedēre to sit, Sanskrit sīdati he sits
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

Word Origin and History for sit up



Old English sittan "to occupy a seat, be seated, sit down, seat oneself; remain, continue; settle, encamp, occupy; lie in wait; besiege" (class V strong verb; past tense sæt, past participle seten), from Proto-Germanic *setjan (cf. Old Saxon sittian, Old Norse sitja, Danish sidde, Old Frisian sitta, Middle Dutch sitten, Dutch zitten, Old High German sizzan, German sitzen, Gothic sitan), from PIE root *sed- (1) "to sit" (see sedentary).

With past tense sat, formerly also set, now restricted to dialect, and sate, now archaic; and past participle sat, formerly sitten. In reference to a legislative assembly, from 1510s. Meaning "to baby-sit" is recorded from 1966.

To sit back "be inactive" is from 1943. To sit on one's hands was originally "to withhold applause" (1926); later, "to do nothing" (1959). To sit around "be idle, do nothing" is 1915, American English. To sit out "not take part" is from 1650s. Sitting pretty is from 1916.



also situp, kind of physical exercise, 1955, from the verbal phrase (attested from early 13c.); see sit (v.) + up (adv.). Related: Sit-ups.

Online Etymology Dictionary, © 2010 Douglas Harper

Idioms and Phrases with sit up

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]


Stay up later than usual, as in The nurse sat up with her all night long. [Mid-1500s]


Sit with the spine erect, as in She was always telling the students to sit up. [Early 1700s]


Become suddenly alert, as in The students sat up when he brought up the test. The same sense appears in the related sit up and take notice, as in When he mentioned the arrival of a movie star, they all sat up and took notice. [Late 1800s]


In addition to the idioms beginning with sit

  • sit at one's feet
  • sit back
  • sit bolt upright
  • sit by
  • sit down
  • sit in
  • sit on
  • sit on one's hands
  • sit out
  • sit pretty
  • sit through
  • sit tight
  • sit up
  • sit well with

also see:

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