The noun is a part of speech. A noun names a person, a place, a thing, or an idea.
Some nouns name a person.
Examples: Mary, teacher, Daddy, Grandpa, doctor, baby
Some nouns name a place.
Examples: school, home, County Hospital, playground
Some nouns name a thing.
Examples: dog, Main Street, ball, hamburger
Some nouns name an idea.
Examples: sadness, love, fear, hope (these nouns are often feelings)
A noun that does not name a specific person, place, or thing is called a common noun. Common nouns begin with a lowercase letter.
A noun that names a specific person, place, or thing is called a proper noun. Proper nouns must be capitalized.
common noun: dog
proper noun: Rover
common noun: street
proper noun: Main Street
common noun: school
proper noun: Central Middle School
common noun: teacher
proper noun: Mr. Smith
Some nouns can be common sometimes and proper other times. The word mother is one of those words.
That lady is my mother. You are talking about the lady so mother is lowercase.
Dear Mother, I hope you are well. Now you are talking to your mother and calling her by name, so you must capitalize the word.
Remember: a noun is a part of speech that names a person, a place, a thing, or an idea. Capitalize proper nouns because they name a specific person, place, or thing.