An archaic term, in general; according to the wildly variable and sometimes suspect Wikipedia, it is a term taken from an even more archaic term for food for livestock. “Soldiers are the metaphorical food for enemy cannon fire.” Wikipedia defines the expression further as, “…an informal, derogatory term for combatants who are regarded … as expendable in the face of enemy fire … or to distinguish expendable low-grade or inexperienced combatants from supposedly more valuable veterans.”
Expendable is the operative word, and expendable without much regret on the part of the credentialed elite the political, social or military elite because the expected goal is considered worth the sacrifice, especially if the sacrifice is borne by others. Reading this week about the sexual violence reported reluctantly in many cases by German media as being perpetrated on a grand scale by recent Middle Eastern migrants masquerading as war refugees on women in German cities on this last New Years Eve gave me a sickening new understanding of the concept.