cylinder

The word “cylinder” means a solid or hollow object with straight parallel sides and a circular cross-section, like a tube or a can. In plain terms, a tube-shaped object or space — from a gas canister to the chamber inside a car engine.

“Cylinder” is pronounced SIH-lihn-duh (/ˈsɪləndɚ/ in IPA).

Here is “cylinder” used in a sentence: “The candle was shaped like a perfect cylinder.”

“Cylinder” is a noun.

The word “cylinder” comes from Ancient Greek. From Ancient Greek kulindros, from kulindo ("I roll"), via Latin cylindrus and Middle French cylindre.

“Cylinder” is a fairly common word in modern English.

“Cylinder” has 3 distinct senses listed in this dictionary. The most common is: a solid or hollow object with straight parallel sides and a circular cross-section, like a tube or a can.

Strictly, no. A prism has two identical flat polygon ends joined by flat faces, while a cylinder's ends are circles joined by one curved surface. A cylinder's volume is found the same way (base area times height), but because a circle is not a polygon, mathematicians do not class the cylinder as a prism.

The usual school answer is three faces (two flat circular ends plus one curved surface), two curved edges where the circles meet the side, and no vertices. Some stricter textbooks count only flat surfaces as faces and would say two, so check which definition your course uses.

The number tells you how many cylinders — the chambers in which the pistons move — the engine contains. More cylinders generally allow more power and smoother running, while fewer cylinders usually give better fuel economy, which is why most small cars use four.

It comes from engines: each cylinder must ignite its fuel at the right moment, and only when every cylinder fires correctly does the engine deliver full power. Figuratively, a person or team "firing on all cylinders" is performing at their very best.