Simply put WorldCat is short for World Catalog. 

In fancier terms, it is a union catalog that has itemized the collections of more than 69,000 libraries, in more than 100 countries.

WorldCat has almost 1.3 billion assets listed, both physical and digital.  It is the world’s largest bibliographic database!

The Academic version of WorldCat (FirstSearch) allows a user to search the catalog, and find LC and Dewey call numbers, as well as LC subject headings.  Both versions show you descriptors, citation styles, and locations.  But open WorldCat is free! 

WorldCat fills a request via search sharing every 4 seconds!  Checkout the links page for more amazing facts.