Aπό το google: " General. Differential ground rent and absolute ground rent are concepts used by Karl Marx in the third volume of Das Kapital to explain how the capitalist ..."
Αν παρά τα φτωχά ελληνικά μου κατάλαβα καλά τι θέλει να πει ο ποιητής, τότε ο όρος είναι floating signal ground:
" To measure the voltage of a single point, a reference point must be selected to measure against. This common reference point is called "ground" and considered to have zero voltage. This signal ground may not be connected to a power ground. A system where the system ground is not connected to another circuit or to earth (though there may still be AC coupling) is often referred to as a floating ground."