Money that hasn't found its rightful owner. Might be tax rebates, utility deposits, rebates, etc. It's required to be turned over to the state treasurer. Since you have Ohio as your location, here's the Ohio site:
http://www.tos.ohio.gov/ForYou/Default.aspx?Section=Unclaimed Funds
Be sure to check all states you and DH and kids have lived in and all names you have used (maiden name, etc)