Definition: The word "noun" refers to an entity that has a definite meaning or function, such as a person, place, thing, or idea. A noun is typically followed by a word ending in -er (such as "cat", "house", "car") or "-ing" (such as "happy", "big", "beautiful"). Nouns can be classified into various types based on their functions and properties. For example, nouns like "book" are often used to refer to the physical object they represent, while "life" is often used to describe a person's existence. The word "noun" has numerous synonyms that can vary depending on the context in which it is used.