An abstract noun expresses an intangible idea or broad concept (eg bureaucracy, equipment, elevation, initiative), whereas a concrete noun describes a physical object (eg elephant, plate, spade, towel). General nouns refer to classes of objects, concepts, animals or people (eg fruit, livestock, program, team):

You can select nouns from different levels of abstraction to suit your topic. The choice depends on the context, and how much detail is needed:

Many abstract nouns are useful when they capture a broad idea (eg democracy, freedom, infrastructure, literacy). But some add words to a sentence without adding meaning. In this case, you can strengthen your writing by taking out the abstract nouns: