What are compound nouns?

[Hunnybunny]

I need your help once again. I'm a little bit confused. What are compound nouns? What would be the criteria that would classify two words as compound nouns?

If you're given words like: playground, policeman, plastic surgery and taxi stand, which ones would be considered compound?

Thanks a lot in advance!

[Conchita]

All your examples are compound nouns, which are combinations of two or more words. For more information, you can have a look at:

http://www.edufind.com/english/grammar/NOUNS4.cfm
http://en.wikipedia.org/wiki/English_compound
http://www.bbc.co.uk/worldservice/learningenglish/grammar/learnit/learnitv155.shtml

[Hunnybunny]

Thanks, Ms. Conchita! I really appreciate it!