What’s the difference between a regular foreclosure and an REO foreclosure?

I’ve been looking up foreclosures at the county office to buy a foreclosure (the ones about to be auctioned). Someone said I should be looking at REO foreclosures. What’s the difference, and how do I buy one and or get info on these?

Tagged as: Auction, belongings-out, buy-one, called-said, completley-out, county, sells-during, the-county, the-home, the-ones, true