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cyl·in·der (silən-dər)
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n.
1. Mathematics
a. The surface generated by a straight line intersecting and moving along a closed plane curve, the directrix, while remaining parallel to a fixed straight line that is not on or parallel to the plane of the directrix.
b. The portion of such a surface bounded by two parallel planes and the regions of the planes bounded by the surface.
c. A solid bounded by two parallel planes and such a surface, especially such a surface having a circle as its directrix.
2. A cylindrical container or object.
3. Engineering
a. The chamber in which a piston of a reciprocating engine moves.
b. The chamber of a pump from which fluid is expelled by a piston.
4. The rotating chamber of a revolver that holds the cartridges.
5. Any of several rotating parts in a printing press, especially one that carries the paper.
6. Archaeology A cylindrical stone or clay object with an engraved design or inscription.

[Latincylindrus, fromGreekkulindros, fromkulindein, to roll.]
(click for a larger image)
cylinder
To calculate the volume of a right circular cylinder, multiply the area of the base by the altitude.

The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2019 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
 

Indo-European & Semitic Roots Appendices

    Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:

    Indo-European Roots

    Semitic Roots

    The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.

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