What is Priority?

Legal Definition
Going before; opposed to posteriority. (q. v.)

2. He who has the precedency in time has the advantage in right, is the maxim of the law; not that time, considered barely in itself, can make any such difference, but because the whole power over a thing being secured to one person, this bars all others from obtaining a title to it afterwards. 1 Fonb. Eq. 320.

3. In the payment of debts, the United States are entitled to priority when the debtor is insolvent, or dies and leaves an insolvent estate. The priority was declared to extend to cases in which the insolvent debtor had made a vol-untary assignment of all his property, or in which his effects had been attached as an absconding or absent debtor, on which an act of legal bankruptcy had been committed. 1 Kent, Com. 243; 1 Law Intell. 219, 251; and the cases there cited.

4. Among common creditors, he who has the oldest lien has the preference; it being a maxim both of law and equity, qui prior est tempore, potior est jure. 2 John. Ch. R. 608. Vide Insolvency; and Serg. Const. La*, Index, h. t.
-- Bouviers Law Dictionary
Legal Definition
A legal preference or precedence. When two persons have similar rights in respect of the same subject-matter, but one is entitled to exercise his right to the exclusion of the other, he is said to have priority. In old English law. An antiquity of tenure, in comparison with one not so ancient. CowelL
-- Black's Law Dictionary
Legal Definition
The state of being first in point of time.
-- Ballentine's Law Dictionary