Mawson, C.O.S., ed. (1870–1938). Roget’s International Thesaurus. 1922.

Class IV. Words Relating to the Intellectual Faculties
Division (I) Formation of Ideas
Section VI. Extension of Thought
2. To the Future

512. Omen.

   NOUN:OMEN, portent, presage, prognostic, augury, auspice; sign (indication) [See Indication]; harbinger (precursor) [See Precursor]; yule candle, yule log or clog.
  bird of ill omen; halcyon birds; signs of the times; gathering clouds, thunder, lightning, rainbow, comet, shooting star; rain of blood, warning [See Warning].
  prefigurement [See Prediction]; adytum [See Prediction].
   ADJECTIVE:ILL-BODING, ill-omened, inauspicious.
   QUOTATION:Auspicium melioris ævi.