cyl‧in‧der /ˈsɪləndə, ˈsɪlɪndə $ -ər/ noun [countable]
[Date: 1500-1600; Language: Latin; Origin: cylindrus, from Greek, from kylindein 'to roll']

1. a shape, object, or container with circular ends and long straight sides ⇒ tube:
The gases are stored in cylinders.

2. the tube within which a piston moves forwards and backwards in an engine:
a four-cylinder engine

3. be firing/running on all cylinders informal to be operating or performing very well:
The team is firing on all cylinders.

[TahlilGaran] Dictionary of Contemporary English ▲

square a shape with four straight sides that are equal in length and four angles of 90 degrees
circle a round shape that is like an O
semicircle half a circle
triangle a shape with three straight sides and three angles
rectangle a shape with four straight sides and four angles of 90 degrees
oval a shape like a circle, but that is longer than it is wide
cylinder an object in the shape of a tube
cube a solid object with six equal square sides
pyramid a shape with a square base and four triangular sides that meet in a point at the top
sphere a shape like a ball
circular/round shaped like a circle:
a circular table
semicircular shaped like a semicircle:
a semicircular arch above the door
triangular shaped like a triangle:
sails divided into triangular sections
rectangular shaped like a rectangle:
a simple rectangular building
cylindrical shaped like a cylinder:
The statue is on top of a tall cylindrical column.
spherical shaped like a ball:
The planet Saturn is not completely spherical.

[TahlilGaran] English Thesaurus ▲