Meaning

noun a source of materials to nourish the body

noun the financial means whereby one lives

noun the act of sustaining life by food or providing a means of subsistence

originFrom Middle English sustenaunce, from Old French sustenance, from sustenir with the suffix -ance, from Vulgar Latin *sustenire, from Latin sustinere. Compare also Late Latin sustinentia. Equivalent to sustain + -ance.

Etymology from Wiktionary, CC BY-SA 3.0