sovereign n.

late 13c., soverain, "superior, ruler, master, one who is superior to or has power over another," from Old French soverain "sovereign, lord, ruler," noun use of adjective meaning "highest, supreme, chief" (see sovereign (adj.)). Specifically by c. 1300 as "a king or queen, one who exercises dominion over people, a recognized supreme ruler of a realm." Also of Church authorities and heads of orders or houses as well as local civic officials.

Middle English had a tendency to add an unetymological -t to it, as in pheasant, tyrant. The spelling also was influenced by folk-etymology association with reign. Middle English Compendium lists 38 spellings including suffereignes; Elizabeth I, who was one, spelled it seven different ways. Milton prints it sovran, as though from Italian sovrano.

The meaning "gold coin worth 22s 6d" is attested from late 15c.; the value of it changed 1817 to 1 pound. In the political writings of 17c.-18c. it often has a sense of "the populace as the source of political power, the community in its collective and legislative capacity" and can be opposed to monarch.

Should it be argued, that a government like this, where the sovereignty resides in the whole body of the people, is a democracy ; it may be answered, that the right of sovereignty in all nations is unalienable and indivisible, and does and can reside nowhere else ; but, not to recur to a principle so general, the exercise, as well as the right of sovereignty, in Rome, resided in the people, but the government was not a democracy. In America, the right of sovereignty resides indisputably in the body of the people, and they have the whole property of land. [John Adams, "Defence of the Constitutions of Government of the United States of America," 1787-88]

early 14c., of persons, "great, superior, supreme;" mid-14c., "having supreme power;" from Old French soverain "highest, supreme, chief," from Vulgar Latin *superanus "chief, principal" (source also of Spanish soberano, Italian soprano), from Latin super "over" (from PIE root *uper "over"). Of remedies or medicines, "potent in a high degree," from late 14c.