Is 'universe' a concrete noun or an abstract noun?

Answer 1

The noun 'universe' can have different definitions as evidenced when you look up the word in a dictionary. Normally when scientists and laypeople use the word, they are referring to the whole of physical reality. Its important to note that 'universe' is a collective noun because by its very nature it refers to 'all things' and not just to 'one thing'. This first definition of 'universe' is concrete because it is referring to all the things that we can perceive with our senses. Everything that we see, hear, touch, taste, and smell is part of the universe. So 'universe' as the word is usually employed is a concrete noun. However, 'universe' can also be abstract when it refers to a mathematical set for example or a field of human activity or experience. Sometimes scientists use the noun to refer to a theoretical domain of space, time, matter, and energy that is causally disconnected from our physical whole. This use of the word is also abstract because by definition we could never physically interact with another universe or other universes if they even exist.