late 14c., primacie, "preeminent position, supremacy, condition of being first in order, power, or importance," from Old French primacie (14c.; Modern French primatie) and directly from Medieval Latin primatia "office of a church primate" (12c.), from Late Latin primas (genitive primatis) "principal, chief, of the first rank," from primus "first" (see prime (adj.)).

word-forming element forming nouns meaning "rule or government by," from French -cratie or directly from Medieval Latin -cratia, from Greek -kratia "power, might; rule, sway; power over; a power, authority," from kratos "strength," from PIE *kre-tes- "power, strength," suffixed form of root *kar- "hard." The connective -o- has come to be viewed as part of it. Productive in English from c. 1800.

"state of being extremely precise or exact; conformity to truth," 1660s, from accurate + abstract noun suffix -cy.

early 15c., "robbery upon the sea, the practice of robbing on the high seas," from Medieval Latin piratia, from classical Latin, Greek peirateia "piracy," from peiratēs "brigand, pirate" (see pirate (n.)).

Specifically, in the law of nations, the crime of depredations or wilful and aggressive destruction of life or property committed on the seas by persons having no commission or authority from any established state. As commonly used it implies something more than a simple theft with violence at sea, and includes something of the idea of general hostility to law. According to the opinion of some, it implies only unlawful interference with a vessel ; according to others, it includes also depredations on the coast by a force landing from the sea. [Century Dictionary]

c. 1600; see effeminate + -acy.

1670s; see illegitimate + -acy.

1640s, see indeterminate + -acy.

"condition of dying without leaving a valid will," 1740, from intestate + -acy.

"office of a magistrate," 1570s; see magistrate + -acy.

1540s, from supreme + -acy, or from Latin supremitatem (nominative supremitas). Supremity in same sense is from 1530s.