'Sustainment' definitions:

Definition of 'sustainment'

From: WordNet
noun
The act of sustaining life by food or providing a means of subsistence; "they were in want of sustenance"; "fishing was their main sustainment" [syn: sustenance, sustentation, sustainment, maintenance, upkeep]

Definition of 'Sustainment'

From: GCIDE
  • Sustainment \Sus*tain"ment\, n. The act of sustaining; maintenance; support. --Milton. Lowell. [1913 Webster]