Definition:Cylinder/Axis

From ProofWiki
Jump to: navigation, search

Definition

Cylinder.png


In the words of Euclid:

The axis of the cylinder is the straight line which remains fixed and about which the parallelogram is turned.

(The Elements: Book $\text{XI}$: Definition $22$)


In the above diagram, the axis of the cylinder $ACBEFD$ is the straight line $GH$.


Linguistic Note

The plural of axis is axes, which is pronounced ax-eez not ax-iz.

Compare basis.