Emily Dickinson Lexicon

AP'PAN-AGE, n. [Fr. apanage, an estate assigned to a younger son for his maintenance; an appendix, dependence, appurtenance; It. appannaggio, an appendage. If this word is from the panage, panagium of the middle ages, it is from panis, food, provision; It. panaggio, provision. This is probably the true origin of the word.]

1. Lands appropriated by a prince to the maintenance of his younger sons, as their patrimony; but on condition of the failure of male offspring, they were to revert to the donor or his heir. From the appanage it was customary for the sons to take their surnames. – Spelman.
2. Sustenance; means of nourishing. Wealth … the appanage of wit. – Swift.