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

With all those cylinders firing, the only thing left should have been the release of her first official album—but that turned out to be a winding road that nearly broke her down. —Regina Cho, VIBE.com, 18 June 2025

As the piston rises again, compression of the fuel and air happens as the vacuum created underneath the cylinder pulls in another batch of fuel and air. —New Atlas, 14 June 2025

After the delivery, the sealed cylinder at the wheel's center could be flipped on its side and turned into a human habitat. —Julian Dossett, Space.com, 12 June 2025

Or what happens if the cylinder is not perfectly spherical? —Steven Strogatz, Quanta Magazine, 12 June 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