The term engineering drawing is the way of representing the three-dimensional object in a two-dimensional way.
The engineering drawing also provides information about the object such as its shape, size, material and manufacturing process, etc. The main purpose of the engineering drawing is to capture all the geometrical features of a product or a component.
For example, let me illustrate with an example here the image given below shows a 3D component drawn using 3D software.
If I need to manufacture the above component, then I need to communicate with the manufacturer. The manufacture will be unaware of the dimensions of the component, whether to manufacture the component in a larger size or in a smaller size, and also unaware of the diameter of the hole.
So instead of providing a 3D image if I provide him with the image given above he can easily understand what are the dimensions of it, the value of the hole diameter, and other much more specifications in an easy and meaningful manner.
So as a conclusion, engineering drawing is a way of representing the technical specifications and other geometrical specifications in a very much detailed manner