Cylindrical means shaped like a cylinder: a tube or column with circular ends and straight sides, like a soup can or a paper towel roll. If you trace your finger around the top of a soda can and then slide it straight down to the bottom, you've followed a cylindrical shape.

Cylindrical objects are everywhere once you start noticing them: batteries, water bottles, pipes, tree trunks, and even some skyscrapers. The shape works well for containers because it's strong and efficient, with no corners or weak points. Engineers often choose cylindrical designs when building things that need to hold pressure, like submarine hulls or scuba tanks.

In math and science, people describe things as cylindrical when they need to be precise about shape. A scientist might note that a particular bacterium is cylindrical rather than spherical (ball-shaped) or cubical (box-shaped).