c. 1300, "means of living, subsistence, livelihood," from Old French sostenance "support, aid" (Modern French soutenance), from Late Latin sustinentia "endurance," from present participle stem of Latin sustinere (see sustain). Meaning "action of sustaining life by food" is from late 14c. Sense of "nourishment" is recorded from late 15c. Related: Sustenant.[sustenance etymology, sustenance origin, 英语词源]