a noun that may be preceded by an article or other limiting modifier and that denotes any or all of a class of entities and not an individual, as man, city, horse, music.
Half of the phrases were proper nouns and the remaining were mostly common noun phrases.
Capital letters are an important cue to readers and translators that a term is a proper noun, not a common noun.
British Dictionary definitions for common noun
common noun
noun
1.
(grammar) a noun that refers to each member of a whole class sharing the features connoted by the noun, as for example planet, orange, and drumCompare proper noun