What is mean by ABSTRACT NOUN and MATERIAL NOUN???

Abstract noun:

Please follow the link given below:

https://www.meritnation.com/ask-answer/question/what-is-an-abstract-noun/nouns/3785750 

 Material Noun:

 A Material Noun denotes substances that can be touched, smelt and perceived by our sense organs.

For Example: air, water, iron, paper, ink, etc.