meal ticket vs sustenance

meal ticket and sustenance both are nouns.

Word	Noun	Adjective	Verb	Adverb
meal ticket	Yes	No	No	No
sustenance	Yes	No	No	No

As nouns, sustenance is a hypernym of meal ticket; that is, sustenance is a word with a broader meaning than meal ticket:

Other hypernyms of meal ticket include bread and butter, keep, livelihood, living, support.

meal ticket (noun)	sustenance (noun)
coupon redeemable at a restaurant and entitling the holder to a meal	the act of sustaining life by food or providing a means of subsistence
a source of income or livelihood	a source of materials to nourish the body
	the financial means whereby one lives