Meta-search engines

[CAPUTO CORINNE]

Would someone please explain to me what a meta-search engine is?  
Could you give me some examples please?  I am in a marathon to learn 
as much of the internet advanced, etc. for teaching a class and i've 
come across this term, but would someone define it for me and give me 
some examples.  I've heard it being used in various places but yet to 
see a really good definition, etc.  thanks in advance.  cori
Cori Caputo
Librarian
NMSUA at Alamogordo
Alamogordo, NM 88311
email:cori at nmsua.nmsu.edu
office: 505-439-3628
fax:505-439-3657