Ought1 forms its negative in a number of ways. Ought not occurs in all types of speech and writing and is fully standard: The conferees ought not to waste time on protocol.Oughtn't, largely a spoken form, is found mainly in the Midland and Southern dialects of the United States, where it is almost the universal form. Hadn't ought is a common spoken form in the Northern dialect area. It is sometimes condemned in usage guides and is uncommon in educated speech except of the most informal variety. Didn't ought and shouldn't ought are considered nonstandard. Both positive and negative forms of ought are almost always followed by the infinitive form: We ought to go now. You ought not to worry about it. Occasionally, to is omitted after the negative construction: Congress ought not adjourn without considering this bill.
"something," Old English awiht "aught, anything, something," literally "e'er a whit," from Proto-Germanic *aiwi "ever" (from PIE *aiw- "vital force, life, long life, eternity;" see eon) + *wihti "thing, anything whatever" (see wight). In Shakespeare, Milton and Pope, aught and ought occur indiscriminately.
"nothing, zero," faulty separation of a naught (see naught; cf. also adder for the separation problem).
Old English ahte "owned, possessed," past tense of agan "to own, possess, owe" (see owe). As a past tense of owe, it shared in that word's evolution and meant at times in Middle English "possessed" and "under obligation to pay." It has been detached from owe since 17c., though he aught me ten pounds is recorded as active in East Anglian dialect from c.1825. As an auxiliary verb expressing duty or obligation (late 12c., the main modern use), it represents the past subjunctive.
"zero, cipher," 1844, probably a misdivision of a nought (see nought; for misdivision, see N); meaning probably influenced by aught "anything."