The term death tax is used by those opposed to the legal concept of an estate or inheritance tax, which is a tax on the value of a deceased individual's assets before they are passed on to heirs. It is mainly used by conservatives.
The term originated in a famous memorandum written by Republican pollster Frank Luntz. He recommended that the party use the term death tax when referring to the estate tax, writing that the term death tax "kindled voter resentment in a way that inheritance tax and estate tax do not" [1]. Most journalists have not adopted the phrase, and will only report it in the context of a quotation, or place quotation marks around the word.