What is "solid of revolution"

Solid \Sol"id\, n.

1. A substance that is held in a fixed form by cohesion among its particles; a substance not fluid.

2. (Geom.) A magnitude which has length, breadth, and thickness; a part of space bounded on all sides.

   Solid of revolution. (Geom.) See Revolution, n., 5.

n. A solid produced by taking a particular two-dimensional curve and rotating it through 360° about an axis. The curve will sweep out a surface, and the region inside the surface defines a solid.

In mathematics, engineering, and manufacturing, a solid of revolution is a solid figure obtained by rotating a plane curve around some straight line (the axis) that lies on the same plane.

Assuming that the curve does not cross the axis, the solid's volume is equal to the length of the circle described by the figure's centroid multiplied by the figure's area ( Pappus's second centroid Theorem).

A representative disk is a three- dimensional volume element of a solid of revolution. The element is created by rotating a line segment (of length ) around some axis (located units away), so that a cylindrical volume of units is enclosed.