I have URL as "www.xyz.ac.in".
Than what is meaning of "ac" in URL?
Like "in" stands for India, "xyz" is domain and "www" is world wide web...
'ac' seems to mostly stand for "academic", so it's used by some universities and colleges.
However that's not always the case. There are some other usages as per the article here, including even PirateBay: