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

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

Some practice getting into character, while others do sit-ups and pull-ups to make their muscles pop. —Kristen Baldwin, Entertainment Weekly, 4 Nov. 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