cylinder

UK: /ˈsɪlɪndə^r/ US: /ˈsɪlɪndɚ/ ,(sil′in dər)

WordReference Random House Learner's Dictionary of American English © 2025

cyl•in•der /ˈsɪlɪndɚ/   n. [countable]

1. Mathematics a surface shape or solid having long straight sides and two flat round ends;
   a shape resembling a tube with a top and bottom.
2. any object or part shaped like a cylinder, as the part of a revolver holding the bullets, or a part of an engine where a piston compresses the air and fuel mixture.

cyl•in•dered, adj. 

WordReference Random House Unabridged Dictionary of American English © 2025

cyl•in•der  (sil′in dər), n. 

1. Mathematics [Geom.] a surface or solid bounded by two parallel planes and generated by a straight line moving parallel to the given planes and tracing a curve bounded by the planes and lying in a plane perpendicular or oblique to the given planes.
2. any cylinderlike object or part, whether solid or hollow.
3. Military the rotating part of a revolver, containing the chambers for the cartridges.
4. Hydraulics (in a pump) a cylindrical chamber in which a piston slides to move or compress a fluid.
5. (in an engine) a cylindrical chamber in which the pressure of a gas or liquid moves a sliding piston.
6. (in certain printing presses)
   • Printing a rotating cylinder that produces the impression and under which a flat form to be printed from passes.
   • Printing either of two cylinders, one carrying a curved form or plate to be printed from, that rotate against each other in opposite directions.
7. Building (in certain locks) a cylindrical device for retaining the bolt until tumblers have been pushed out of its way.
8. Building (in a screw or cylindrical gear) an imaginary cylindrical form, concentric to the axis, defining the pitch or the inner or outer ends of the threads or teeth.
9. Computing the tracks of a magnetic disk that are accessible from a single radial position of the access mechanism.
10. Textiles the main roller on a carding machine, esp. the roller covered with card clothing that works in combination with the worker and stripper rollers in carding fibers.
11. Archaeology a cylindrical or somewhat barrel-shaped stone or clay object bearing a cuneiform inscription or a carved design, worn by the Babylonians, Assyrians, and kindred peoples as a seal and amulet.

v.t. 

12. to furnish with a cylinder or cylinders.
13. to subject to the action of a cylinder or cylinders.

• Greek kýlindros roller, cylinder, akin to kylíndein to roll
• Latin cylindrus
• 1560–70

cyl′in•der•like′, adj. 

Collins Concise English Dictionary © HarperCollins Publishers::

cylinder / ˈsɪlɪndə/ noun

1. a solid consisting of two parallel planes bounded by identical closed curves, usually circles, that are interconnected at every point by a set of parallel lines, usually perpendicular to the planes. Volume base area × length
2. a surface formed by a line moving round a closed plane curve at a fixed angle to it
3. any object shaped like a cylinder
4. the chamber in a reciprocating internal-combustion engine, pump, or compressor within which the piston moves
5. the rotating mechanism of a revolver, situated behind the barrel and containing cartridge chambers
6. any of the rotating drums on a printing press
7. Also called: cylinder seal a cylindrical seal of stone, clay, or precious stone decorated with linear designs, found in the Middle East and Balkans: dating from about 6000 bc

Etymology: 16th Century: from Latin cylindrus, from Greek kulindros a roller, from kulindein to roll

ˈcylinder-ˌlike adjective