/ ˈsʌstənəns; NAmE / noun [ U ] ( formal )
1.
the food and drink that people, animals and plants need to live and stay healthy :
There's not much sustenance in a bowl of soup.
( figurative )
Arguing would only give further sustenance to his allegations.
2.
sustenance (of sth) the process of making sth continue to exist :
Elections are essential for the sustenance of parliamentary democracy.
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WORD ORIGIN
Middle English : from Old French soustenance , from the verb soustenir , from Latin sustinere , from sub- from below + tenere hold.