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

According to the outlet, Nelson regularly does sit-ups, arm rolls, leg lifts and jogs in place to keep his physical health in order. —Jack Irvin, PEOPLE, 22 Dec. 2025

However, sit-ups work your entire core while crunches target your abdominal muscles. —Rikkilynn Shields Hannigan, Health, 16 Dec. 2025

Verb

But there was something about the formation of these weather systems swirling across his screen that made Tangang sit up. —Helen Regan, CNN Money, 6 Dec. 2025

In April 2018, Justin told PEOPLE the exciting milestones his then-6-month-old had reached, including turning, sitting up, crawling and bonding with his older sister. —Katie Mannion, PEOPLE, 1 Dec. 2025

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