obsession
obsession: n.
1 the act of obsessing or the state of being obsessed.
2 a persistent idea or thought dominating a person's mind.
3 a condition in which such ideas are present. øøobsessional adj. obsessionalism n. obsessionally adv. [L obsessio (as OBSESS)]

oblivion
oblivion: n.
1 a the state of having or being forgotten. b disregard; an unregarded state.
2 an amnesty or pardon. øfall into oblivion be forgotten or disused. [ME f. OF f. L oblivio -onis f. oblivisci forget]

oscillate
oscillate: v.
1 intr. & tr. a swing to and fro like a pendulum. b move to and fro between points.
2 intr. vacillate; vary between extremes of opinion, action, etc.
3 intr. Physics move with periodic regularity.
4 intr. Electr. (of a current) undergo high-frequency alternations as across a spark-gap or in a valve-transmitter circuit.
5 intr. (of a radio receiver) radiate electromagnetic waves owing to faulty operation. øøoscillation n. oscillator n. oscillatory adj. [L oscillare oscillat- swing]

oestrogen
oestrogen: n. (US estrogen.
1 any of various steroid hormones developing and maintaining female characteristics of the body.
2 this hormone produced artificially for use in oral contraceptives etc. øøoestrogenic adj. oestrogenically adv. [OESTRUS + -GEN]

objectively
omnibus
omnibus: n. & adj. --n.
1 formal = BUS.
2 a volume containing several novels etc. previously published separately. --adj.
1 serving several purposes at once.
2 comprising several items. [F f. L (dative pl. of omnis), = for all]

other
other: adj., n. or pron., & adv. --adj.
1 not the same as one or some already mentioned or implied; separate in identity or distinct in kind (other people; use other means; I assure you, my reason is quite other).
2 a further; additional (a few other examples). b alternative of two (open your other eye) (cf. every other).
3 (prec. by the) that remains after all except the one or ones in question have been considered, eliminated, etc. (must be in the other pocket; where are the other two?; the other three men left).
4 (foll. by than) apart from; excepting (any person other than you). --n. or pron. (orig. an ellipt. use of the adj., now with pl. in -s.
1 an additional, different, or extra person, thing, example, etc. (one or other of us will be there; some others have come) (see also ANOTHER each other).
2 (in pl.; prec. by the) the ones remaining (where are the others?). --adv. (usu. foll. by than) disp. otherwise (cannot react other than angrily). °In this sense otherwise is standard except in less formal use. øno other archaic nothing else (I can do no other). of all others out of the many possible or likely (on this night of all others). on the other hand see HAND . the other day (or night or week etc.) a few days etc. ago (heard from him the other day). other-directed governed by external circumstances and trends. other half colloq. one's wife or husband. the other place Brit. joc. Oxford University as regarded by Cambridge, and vice versa. other ranks soldiers other than commissioned officers. the other thing esp. joc. an unexpressed alternative (if you don't like it, do the other thing). other things being equal if conditions are or were alike in all but the point in question. the other woman a married man's mistress. the other world see WORLD . someone (or something or somehow etc.) or other some unspecified person, thing, manner, etc. [OE other f. Gmc]