A proper noun is the name of a particular person, place, organization, or thing. Proper nouns begin with a capital letter. Examples are `Margaret', `London', and `the United Nations'. Compare common noun. A noun belonging to the class of words used as names for unique individuals, events, or places. Also called proper name. a noun such as 'James', 'New York', or 'China' that is the name of one particular thing and is written with a capital letter noun