I guess INF stand for infinity but that doesn't make any sense.
What do you think?
p.s.
A google search for this gives us little helpful results and some definition for the two folders. Though I can't find what is INF meant.
The META-INF directories related to .jar files. They contain the manifest (list of contents) of a jar and are created when you write a jar file...
The WEB-INF directory contains a heirarcy in which you'll find the necessary configuration information for your web application...
INF is an abbreviation for Information (not infinity in this case).