noun (n)

• a source of materials to nourish the body(noun.food)

  Synonym:
  aliment, alimentation, nourishment, nutriment, nutrition, victuals
  

  source: wordnet30
• the financial means whereby one lives(noun.possession)

  Synonym:
  bread and butter, keep, livelihood, living, support
  

  source: wordnet30
• the act of sustaining life by food or providing a means of subsistence(noun.act)

  Example:
  They were in want of sustenance.
  

  Synonym:
  maintenance, sustainment, sustentation, upkeep
  

  source: wordnet30
• The act of sustaining; support; maintenance; subsistence; as, the sustenance of the body; the sustenance of life.(noun)

  source: webster1913