Is twin a proper noun

Answer 1

No, the word 'twin' is a common noun, a word for any twin of anything.

A proper noun is the name of a specific person, place, thing, or a title; for example:

• The Olsen Twins, Ashley and Mary Kate, American actors and fashion entrepreneurs
• Minneapolis-St. Paul (Minnesota), The Twin Cities
• Twin Falls, Idaho
• Twin Lakes Lodge, Hurley, NY
• "Twin Dragons", 1992 Jackie Chan movie

Answer 2

No, the plural noun 'twins' is a common noun, a general word for two people or things that are alike; a word for any twins of any kind.

A proper noun is the name or title of a specific person, place or thing; for example, the Minnesota Twins Baseball team or "Twins", a 1988 movie with Arnold Schwarzenegger and Danny DeVito.