Question

What differentiate engineering materials from other materials like paper, water, air, etc?  

Answer 1

Engineering materials are the selected material which are used commonly in product design.Whereas some are made for research to new type of material.

In general engineering materials have defined stresses limit like ultimate tensile strength and yield strength etc ,whereas non engineering materials have not necessarily collection of data.

Most of the engineering materials are so much studied that there is a collection of specific pattern of their behaviour with load whereas it is not collected for non engineering materials.