The words that are used to introduce all living and non-living beings and concepts are called nouns. Examples: rose, water, house, Istanbul, Amy, the Atlantic Ocean, running, etc. Nouns are divided into classes in various ways. Proper Noun: Names given to entities that are unique in the world and that are not identical among other entities. Examples: Asia, Mercury, Brasil, Clara, Tom, World Health Organisation, etc. Common Noun: Common names of beings of the same genus, same species. For example, objects useful for writing, even if their shapes, colors, and sizes are different, are called pens. Examples: pencil, tree, person,