A word coined by Jefferson.

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1793.  He proceeds to act as co-sovereign in the territory.—Tho. Jefferson, ‘Writings’ (1859), iv. 45. (N.E.D.)

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1820.  [The constitution] has wisely made all the departments co-equal and co-sovereign between themselves.—Tho. Jefferson to Mr. Jarvis, Sept. 28.

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