All I can offer, at this late hour, is a bit of food for thought.
From CyberGrammar,
Both count and noncount nouns can be subdivided into concrete and abstract nouns. Concrete nouns are those which have measurable or observable referents, such as table or rain, whereas abstract nouns refer to ideas, emotions and concepts, such as thought, fear and determination.
Although in many instances the distinction between the observable, quantifiable nature of concrete nouns and the abstracted, conceptualised quality of abstract nouns is easy to see, it is important to be aware that very often the distinction is less clear. Often expert grammarians will argue about whether a given noun is concrete or abstract. In the sentence, England has an outstanding national football team, it is debatable whether the noun 'team' is concrete because it refers very specifically to a team of identifiable players or abstract because it refers to the notion of a group of people working collectively together.






