"Web Compliant'

I am starting to learn programming after being out of programming for  
more than twenty years.  I have been reading over and over the phrase  
'web compliant'.  This site does not directly state the words web  
compliance.  Why doesn't w3c.org have a section stating web compliance  
specifications so new commers and others know exactly what is the  
focus.  Many experienced web programmers have not been able to explain  
web compliance.  Is this like the word GREEN?

Thanks for your time,
S/W. Richard Evans
706 968 0026