Is a noun concrete or abstract?

A noun is a name of a person, animal, thing or event. This name can either be concrete or abstract.

a concrete noun names something or someone that one can share universal agreement about its specific meaning and existence. To say that a thing is a book (that is a name hence a noun) will likely have most others agreeing. The same will go for a dog or a computer or even a graduation ceremony. We can experience them with our senses. sight, hearing and touch.

on the overhand if one lables something honesty or love or prejudice, there could be much contradiction as to the accuracy of the statement. Much of this is too subjective to enjoy universal agreement. This then is an abstract noun.