Definition from Nolo’s Plain-English Law Dictionary
Federal taxes assessed on any gift, or combination of gifts, from one person to another that exceeds $13,000 in one year. Several kinds of gifts are exempt from this tax: gifts to tax-exempt charities, gifts to your spouse (limited to $133,000 annually if the recipient isn't a U.S. citizen), and gifts made for tuition or medical bills. In addition to the annual gift tax exclusion, there is a $1 million cumulative tax exemption for gifts. In other words, you can give away a total of $1 million during your lifetime -- over and above the gifts you give using the annual exclusion -- without paying gift taxes.