Volume is the amount of space enclosed by an object or shape, how much 3-dimensional space (length, height, and width) it occupies.
Plane figures like triangle, quadrilaterals and circles do not occupy any space because they lie on a plane. But solid figures like those given below do occupy space.
Every object that occupies space has a volume.
What is volume?
The space occupied by any object is called the volume.
So, the volume of an object is the amount of space occupied by
Volume is measured in "cubic units".
Surface like the page of your book, black board, are called plane surfaces. They do not have any volume but have only area.
A cube is a solid whose length, breadth and height are equal. Therefore, a cube, is taken as the unit of solid to measure the amount of space that a solid occupies.