Definition: Def. 11.21: Cylinder

(Definition 21 from Book 11 of Euclid's “Elements”)

A cylinder is the (solid) figure enclosed when, one of the sides of a rectangle about the right angle remaining (fixed), the parallelogram is carried around, and again established at the same (position) from which it began to be moved.

Modern Formulation

(not yet contributed)

Definitions: 1 2
Proofs: 3 4 5 6 7 8
Propositions: 9 10 11 12 13 14

Thank you to the contributors under CC BY-SA 4.0!



Adapted from (subject to copyright, with kind permission)

  1. Fitzpatrick, Richard: Euclid's "Elements of Geometry"

Adapted from CC BY-SA 3.0 Sources:

  1. Prime.mover and others: "Pr∞fWiki",, 2016