A proper noun is a word that names a specific person, place, or thing, and it always starts with a capital letter. Your own name is a proper noun. So is the name of your school, your street, your town, and your country.

Proper nouns work differently than common nouns, which name general categories. “Dog” is a common noun because it refers to any dog, but “Snoopy” is a proper noun because it names one specific dog. “Ocean” is common, but “Pacific Ocean” is proper. “Month” is common, but “October” is proper.

The capital letter signals something important: this word names a specific, particular thing. Mount Everest names a specific mountain. Abraham Lincoln names a specific president. Proper nouns let us point to exactly who or what we mean.

Some proper nouns contain multiple words, like Grand Canyon or United States of America. Each important word gets capitalized. Small words like “of” and “the” usually stay lowercase unless they're the first word.

When you're writing, proper nouns help your reader know exactly what you're talking about. Instead of saying “a famous inventor created the light bulb,” you can write “Thomas Edison invented the light bulb,” and suddenly the sentence becomes much more specific and informative.