sustentation
Concise Oxford English Dictionary © 2008 Oxford University Press:
sustentation /ˌsʌst(ə)nˈteɪʃ(ə)n/
▶noun formal sustenance.
– origin ME: from OFr., or from L. sustentatio(n-), from sustentare ‘uphold, sustain’, frequentative of sustinere (see sustain).
'sustentation' also found in these Oxford entries:

