noun

1. Geom.
   1. in geometry, a solid figure consisting of two parallel bases in the form of congruent, closed curves joined by a smooth, continuous, closed surface; specif., such a figure (right circular cylinder) having circular bases and a surface perpendicular to the bases
   2. the surface of such a solid
2. anything having the shape of a cylinder, whether hollow or solid; specif.,
   1. the turning part of a revolver, containing chambers for cartridges
   2. the chamber in which the piston moves in a reciprocating engine
   3. the barrel of a pump
   4. on a printing press, a roller carrying the printing plates or the part receiving the impression
   5. a large, hollow, cylindrical clay object with cuneiform inscriptions, or a similar small stone worn on the wrist in ancient times in the Middle East

Etymology: Fr cylindre < L cylindrus < Gr kylindros < kylindein, to roll < IE base *(s)kel-, to bend > calcar, colon