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

Knots Landing star Donna Mills does 100 sit-ups every day, and that’s not all. — Leigh Blickley, Entertainment Weekly, 8 Sep. 2026

Eventually, Rebecca York told Stewart why her son did exactly 538 sit-ups every morning. — Luca Evans, Denver Post, 8 May 2026

Verb

Five additional en-suite bedrooms are spread across the layout, while the domed observatory sits up top to capture the night skies via a 14-inch Meade LX200 GPS telescope. — Wendy Bowman, Robb Report, 6 Nov. 2026

Zvyagintsev spent the next three months learning to breathe without a tube, to sit up, to feed himself. — Joshua Yaffa, New Yorker, 2 Nov. 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