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
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Mentioned in:
Definitions: 1 2
Proofs: 3 4 5 6 7 8
Propositions: 9 10 11 12 13 14
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References
Adapted from (subject to copyright, with kind permission)
 Fitzpatrick, Richard: Euclid's "Elements of Geometry"
Adapted from CC BYSA 3.0 Sources:
 Prime.mover and others: "Pr∞fWiki", https://proofwiki.org/wiki/Main_Page, 2016