The definition of a noun used to be so simple. You may even remember your elementary school teachers telling you a noun was a person, place or thing. Then it got a little more complicated when "idea" was added to the list.
Then it got even more confusing when you asked about "coffee" in "coffee table." Is it a noun or an adjective? What about when you add an apostrophe and "s" to it to show possession? Is it still a noun, or does it then become an adjective? And round and round you go. It may seem exhausting but fear not. Here are all the answers to the eternal "what is a noun?" debate.
There are a lot of definitions for "noun," from the simple list to the complex linguistic explanation, but the best way to explain what it is to discuss what a noun does. Remember when you read that verbs do verb-y things? Well, here are the noun-y things that nouns do:
Not all nouns do all of these things all of the time, and not all the words that do these things are nouns, but by and large, if it looks like a noun and acts like a noun, it's probably a noun.
In English, most nouns are not inherently male or female like they are in many other languages. However, there are a few nouns that indicate masculinity/femininity:
Most English nouns can be made plural simply by adding an "s" to them, but there are a few exceptions.
Common nouns are simply things that exist in mass quantities whereas proper nouns are names of specific things. For example, "building" is a common noun. There are millions of them in the world. They're common. However, the Empire State Building is the name of one specific building. There's only one, and that's its name. It's a proper noun.
Common nouns are not capitalized (unless they begin a sentence, of course), but proper nouns are always capitalized.
Countable nouns are nouns that can be counted and therefore made plural. You can have just one eye, but more likely, you have two eyes. One eye, two eyes - you can count them.
Uncountable (or non-countable) nouns are those that we do not generally pluralize. Most liquids, powders and grains fall into this category. Even though there are many corn flakes in your bowl, you say you eat cereal for breakfast, not cereals. And you put sugar on it, not sugars.
We sometimes pluralize non-countable nouns when we are referring to the container or form in which they come. You order two coffees (one for you, one for your friend), but what you really mean is two cups of coffee. You're counting the cups, not the liquid.
Concrete nouns are those that can be perceived with the five senses. If you can see, taste, smell, touch and/or hear it, it's a concrete noun. If it's a concept or idea (love, peace, hate, justice) that cannot be perceived physically, it's an abstract noun.
Possessive nouns can function in the same way as possessive adjectives and pronouns, but possessive nouns are simply nouns that show possession. They're still nouns, but they function as adjectives or pronouns depending on how you use them.
Nouns are inarguably one of the most important elements of the English language. The function as subjects; they show possession; they pluralize singular words; they act as common and proper words. And the list goes on. With such prominence, it's wise to master your noun knowledge.