A proper noun is a noun used as a name, or as a nominal part of a name, for a specific individual, place or entity. Its naming function differs from the classifying use of a common noun. Capitalization can be a writing convention associated with that distinction, but is not by itself a universal grammatical test.[ref]
In the original example
Dara is a teacher, Dara functions as a name while teacher classifies the person. By contrast, Teacher arrived late can capitalize a common noun merely because it begins the written sentence. A classifier using only the initial capital would confuse these roles.The Universal Dependencies code
PROPN also does not automatically apply to every component of an arbitrarily long name. The scheme retains the appropriate categories for many component words in phrase-like names. Explicit criteria therefore matter when counting names or evaluating linguistic annotation. New to topics? Read the docs here!