[ought] verbal auxiliary [ME oughte (1st & 3d sing. pres. indic.), fr. oughte, 1st & 3d sing. past indic. & subj. of owen to own, owe--more at owe] (12c)--used to express obligation "~ to pay our debts", advisability "~ to take care of yourself", natural expectation "~ to be here by now", or logical consequence "the result ~ to be infinity"
[2]ought vt [ME oughte, 1st & 3d sing. past indic. of owen] (13c) 1 chiefly Scot: possess
2. chiefly Scot: owe [3]ought n (1678): moral obligation: duty [4]ought var of aught