Proper nouns (also called proper names) are the names of unique entities. For example, "Janet", "Jupiter" and "Germany" are proper nouns. Proper nouns are usually capitalized in English and most other languages that use the Latin alphabet, and this is one easy way to recognise them. This fails, however, in German, where nouns of all types are capitalized. The convention of capitalizing all nouns was previously used in English, but has long fallen into disuse.
All other nouns are called common nouns. For example, "girl", "planet", and "country" are common nouns.
Sometimes the same word can function as both a common noun and a proper noun, where one such entity is special. For example: "There can be many gods, but there is only one God." This is somewhat magnified in Hebrew where EL means god (as in a god), God (as in the God), and El (the name of a particular Canaanite god). Read more here...
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