Definition of "GDP"

Economics is a messy discipline: too fluid to be a science, too rigorous to be an art. Perhaps it is fitting that economists’ most-used metric, gross domestic product (GDP), is a tangle too. GDP measures the total value of output in an economic territory. Its apparent simplicity explains why it is scrutinised down to tenths of a percentage point every month.

2013 August 3, “Boundary problems”, in The Economist, volume 408, number 8847

Or take Wikipedia. Supported by investments of time rather than money, it has left the old Encyclopedia Britannica in the dust – and taken the GDP down a few notches in the process.

2017, Rutger Bregman, chapter 5, in Elizabeth Manton, transl., Utopia for Realists, Kindle edition, Bloomsbury Publishing, page 104