Whatever happened to the Gross National Product? How is it different from the Gross Domestic Product?
GDP is the more common figure used internationally, and the US adopted that about 10 or 15 years ago.
"GDP measures the output in a geographical area such as the United States.
GNP is just a little more complicated. It measures the output but considers two factors: (1) It includes value produced abroad by U.S. citizens and their foreign investment and (2) it does not include the production value and foreign investment of foreigners in this country."
There are other definitions on that page which are somewhat more comprehensible. It’s not a long article and easy to read.