Definition of "ought"

There was a certayne lender / which had two detters / the one ought five hondred pence / and the other fifty.

1526, [William Tyndale, transl.], The Newe Testamẽt […] (Tyndale Bible), [Worms, Germany: Peter Schöffer], Luke vij:, folio lxxxvj, recto

[…] witneſſe Ariſtippus, who being vrged with the affection he ought his children, as proceeding from his loynes, began to ſpeake and ſpit […].

1603, Michel de Montaigne, “Of Friendship”, in John Florio, transl., The Essayes […], book I, London: […] Val[entine] Simmes for Edward Blount […], page 90

My hopes wa'n't disappointed. I never saw clams thicker than they was along them inshore flats. I filled my dreener in no time, and then it come to me that 'twouldn't be a bad idee to get a lot more, take 'em with me to Wellmouth, and peddle 'em out. Clams was fairly scarce over that side of the bay and ought to fetch a fair price.

1913, Joseph C. Lincoln, chapter 3, in Mr. Pratt's Patients

Is it a small benefit, that I am placed there […] where I see no drunken comessations, no rebellious routs, no violent oppressions, no obscene rejoicings, nor ought else that might either vex or affright my soul?

1658, Joseph Hall, The Devout Soul, Or, Rules of Heavenly Devotion Also the Free Prisoner, Or, the Comfort of Restraint

There are value judgments that are not reducible to observable matters of fact, and there are oughts that cannot be construed as hypothetical and, therefore, cannot be converted into statements of fact.

1996, Mortimer Jerome Adler, The Time of Our Lives: The Ethics of Common Sense‎

Is there a fallacy involved in deriving an ought from a set of exclusively factual or descriptive premises?

2004, Jacques Maritain, John G. Trapani, Truth Matters: Essays in Honor of Jacques Maritain‎

I go back at eight o'clock to-morrow morning, and have got only three—three oughts an ought—three twos six—sixty pound.

1838 March – 1839 October, Charles Dickens, “Nicholas and His Uncle (to Secure the Fortune Without Loss of Time) Wait upon Mr. Wackford Squeers, the Yorkshire Schoolmaster”, in The Life and Adventures of Nicholas Nickleby, London: Chapman and Hall, […], published 1839, page 24