sit-up

1 of 2

noun

ˈsit-ˌəp 

: a conditioning exercise performed from a supine position by raising the torso to a sitting position and returning to the original position without using the arms or lifting the feet

sit up

2 of 2

verb

sat up; sitting up; sits up

intransitive verb

1

a

: to rise from a lying to a sitting position

b

: to sit with the back erect

2

: to show interest, alertness, or surprise

sit up and take notice

3

: to stay up after the usual time for going to bed

Examples of sit-up in a Sentence

Recent Examples on the Web

Noun

Other Key Bodyweight Core Exercises to Try Crunches and sit-ups are all key movements to support trunk strength. —Helen Carefoot, Flow Space, 27 Jan. 2026

At the time it was eliminated in 2012, the Presidential Fitness Test included a one-mile run, sit-ups, a shuttle run, a sit-and-reach test, and pull-ups or push-ups. —Nuria Martinez-Keel, Oklahoma Voice, 8 Jan. 2026

Verb

Ayanna Harris-Rashid was sitting up in bed, her newborn son latched to her breast, one hand scrolling on her phone, when the police called. —Shoshana Walter, CBS News, 10 Feb. 2026

In the now-viral TikTok video, Mikayla can be seen sitting up in her hospital bed with baby Callum resting on her chest. —Georgia Slater, PEOPLE, 4 Feb. 2026

Word History

First Known Use

Noun

1900, in the meaning defined above

Verb

13th century, in the meaning defined at sense 1a

Rhymes for sit-up

• backup
• blowup
• breakup
• buildup
• checkup
• cleanup
• holdup
• hookup
• lineup
• lockup
• makeup
• markup

Kids Definition

sit-up

noun

ˈsit-ˌəp

: an exercise done by lying on the back and rising up to a sitting position by bending forward at the waist without lifting the feet and returning to the original position