sustentation vs sustenance

sustentation and sustenance both are nouns.

Word	Noun	Adjective	Verb	Adverb
sustentation	Yes	No	No	No
sustenance	Yes	No	No	No

As nouns, sustentation and sustenance are synonyms defined as:

sustentation and sustenance: the act of sustaining life by food or providing a means of subsistence

Other synonyms of sustentation include maintenance, sustainment, upkeep.

sustentation (noun)	sustenance (noun)
the act of sustaining life by food or providing a means of subsistence	the act of sustaining life by food or providing a means of subsistence
	a source of materials to nourish the body
	the financial means whereby one lives