cylinder

noun

cyl·​in·​der ˈsi-lən-dər 

1

a

: the surface traced by a straight line moving parallel to a fixed straight line and intersecting a fixed planar closed curve

b

: a solid or surface bounded by a cylinder and two parallel planes cutting all its elements

especially : right circular cylinder see Volume Formulas Table

2

: a cylindrical body or space: such as

a

: the turning chambered breech of a revolver

b(1)

: the piston chamber in an engine

(2)

: a chamber in a pump from which the piston expels the fluid

c

: any of various rotating members in a press (such as a printing press)

especially : one that impresses paper on an inked form

d

: a cylindrical clay object inscribed with cuneiform inscriptions

cylindered

ˈsi-lən-dərd 

adjective

Phrases

on all cylinders

: with maximum effort or intensity : at full capacity or speed

the economy is running on all cylinders

Examples of cylinder in a Sentence

the cylinder of a revolver

Recent Examples on the Web

Its mighty 12-cylinder heart is mounted transversely, stretching side-to-side across the chassis instead of the front-to-back layout usually used with engines of more than four cylinders. —Will Sabel Courtney, Robb Report, 6 Nov. 2025

Inside the hole, that spin makes the ball roll along the cylinder like a mini-pendulum, converting potential energy into spin and then back again. —Lydia Patrick, MSNBC Newsweek, 5 Nov. 2025

That stage is a silo-like cylinder with a tapered nose cone, measuring 165 feet tall, and weighing more than 200,000 pounds. —Jeffrey Kluger, Time, 5 Nov. 2025

This system operates independently across the front and rear cylinder banks, improving throttle control and response. —New Atlas, 4 Nov. 2025

Word History

Etymology

Middle French or Latin; Middle French cylindre, from Latin cylindrus, from Greek kylindros, from kylindein to roll; perhaps akin to Greek kyklos wheel — more at wheel

First Known Use

1570, in the meaning defined at sense 1a

Phrases Containing cylinder

• cylinder head
• cylinder seal
• graduated cylinder
• right circular cylinder
• vascular cylinder

Kids Definition

cylinder

noun

cyl·​in·​der ˈsil-ən-dər 

1

: a geometric shape composed of two parallel faces of identical size and shape (as circles) and a curved surface that completely connects their borders

2

: a body (as the piston chamber of an engine, the barrel of a pump, or the part of a revolver which holds the cartridges) shaped like a cylinder

cylindrical

sə-ˈlin-dri-kəl

adjective

cylindrically

-dri-k(ə-)lē

adverb