Nouns can be grouped into five categories: (1) persons, (2) places, (3) things, (4) living creatures, and (5) ideas/concepts. Below are some examples for each category.
Persons includes a sister, a grandmother, John, the teacher, fire fighter, Aunt May, a neighbor, the friend, Hoon, a boss, the colleague, a peer, the individual, and Nelson Mandela.
Places can be a school, Texas, a home, a store, Japan, a room, a stadium, the desert, a cave, Australia, a state, Veracruz, and a drawer.
Things can comprise the Statue of Liberty, a car, a computer, a cup, the Great Sphinx, a stapler, a pen or pencil, a fence, a cell phone, and the Oxford English Dictionary.
Living creatures are a lion, a Bengal tiger, a dog, a pig, a Siamese cat, a horse, a dolphin, a caterpillar, a Monarch butterfly, a vole, an American Robin, and a yak.
Ideas and concepts include Buddhism, love, freedom, money, time, the Declaration of Independence, marriage, religion, and Hinduism.
In reading through the lists of nouns, you noticed that some of the nouns are capitalized and others are not. In addition to being a person, place, thing, living creature, or concept, nouns can be common and proper. Common nouns are not capitalized. Proper nouns are capitalized.
So while the nouns adult, country, pastry, dog, and disease are common nouns, the nouns Mother Teresa, Latvia, Buche de Noel, Basenji, and Ebola are all proper nouns.