An omen (also called portent or presage) is a phenomenon that is believed to foretell the future, often signifying the advent of change.
Omens may be considered "good" or "bad", but the term is more often used in a foreboding sense, as with the word "ominous".
Ancient Roman religion employed two distinct types of professional omen readers. Augurs interpreted the flights of birds, while haruspices employed animal sacrifice to obtain the entrails necessary for divination.
Omens may be considered either good or bad depending on their interpretation. The same sign may be interpreted differently by different people or different cultures.
Comets also have been considered to be both good and bad omens. The best-known example is probably Halley's Comet, which was a "bad omen" for King Harold II of England but a "good omen" for William the Conqueror.
Omen seen or heard or even visualized at the initiation of an activity, are said to foretell the outcome of the activity. Omens & portents (Shakun & Utpaats) is a useful branch of India astrology, which includes interpretation of dreams, status of living & non-living items in the environment, sounds produced by human & animals, portents, mode of pacification of adverse omens & portents. It acts as a guide in horary astrology, to clinch the issue when there is a stalemate. Coming events cast their shadows before & it is the ingenuity & skill of the interpreters to decode omens correctly for their profitable usage in their daily life. Treatises on omen (Shakun) have commended that omen has the final say in Election. Omens seen at the start of an action does foretell its success. In case adverse omen is seen or heard or even visualized; the activity should not be initiated.
Omen is a wonderful knowledge which acts like a medicine. Vasant Raj in his treatise titled ‘Vasantraj Shakunan’ - an authoritative book on the subject - has opined that when ephemeral elements (Tithi, Nakshatra, election ascendant etc.) are fully auspicious & efficacious (Uttam & Gunyukta), fortified ascendant & strong Moon is present, but there prevails an inauspicious omen (Shakun) then, nothing materializes regarding election.
Some opine that an election clinched only on the basis of an omen, does not have lasting effects. Some has opined that in the matter like making a theft or the like activities, omen is to considered. The treatises on Hindu /Vedic electional astrology have dilated omens in details in travel elections. On seeing an inauspicious omen, the person should return (not undertake journey), & recite Pranayam (a specific Mantra’s recitation) eleven times & then start the journey. If inauspicious omen is again is seen, then he should return & recite Pranayam 16 times & start the journey. And if inauspicious omen is again observed at the third start of the journey, the journey should be abandoned. Best of the sages agree with this, & from this one may infer the importance given to omens in elections.
One must develop faculty of interpretation of omen seen or heard or even visualized at the initiation of an activity, & use it profitably. In case of adverse omen of high potency, execution of an election should be withheld / postponed.
Interpretation of omens
Exponents have laid down rules to interpret omens, examine potency of an omen & timing of event based on omens. Potency of an omen is examined based on its position with respect from the observer (front / back / left / right / higher & lower level), position of omen in geographical direction (East-South-West-North), time of its observation, motion / speed of the omen, sound produced / heard, expression, place where it is observed.
Here are some items & persons signifying auspicious / favourable & inauspicious / unfavourable omens. The list in no means is exhaustive, but provides adequate information. Omens differ from place to place, country to country & religion to religion.
Items signifying omens
Auspicious items: Following fifty items are auspicious items & seeing them is auspicious at all the times. Curd, milk, rice, pot filled with water, ripe food, mustard, sandal, mirror, fresh green grass (Durva- a kind of grass), conch shell, meat, fish, soil (wet), a bright yellow pigment prepared from urine of cow (Gorochan), cow dung, cow, honey, idol of god, Veena (a musical instrument), fruit, seat of king, flower, black items used to decorate eyes (Anjan / Kajal / Surma), ornaments, hand weapon, beetle leaves, conveyance, palanquin (Palki - man carried conveyance), a covered pot or box to keep medicine or wine (Sharavsanput) , flag, parasol (Chhatra), hand fan, clothes, lotus, Kakash (pot), glowing fire, elephant, goats, drums, device to control elephant (Ankush), tail of animal used to whisk flies (Chaamar), gems, gold, silver, copper, herd of tied animals or an animal whose legs are tied, medicine, drink, tree with fruit, fresh vegetables.
Inauspicious items: A sparkle without smoke, ash, fuel-wood-cow dug cake (Upla), rope, mud, device used to make powder by hammering action (Tilkuta), cotton, husk (Tush), bones, opened hair (untied hair), black item, iron, bark of a tree (Valkal), skin of a tree, black sesame (Til) or black pulse, stone, stool, snake, medicine, oil, raw sugar, boneless meat, empty or broken utensil, salt, dry grass, butter milk, wood, iron chain, rain & wind.
Omens related to persons
Auspicious persons: Sight of the following persons is auspicious: a king, happy Brahmin, prostitute, virgin girl, gentle person, well dressed person sitting on a horse or ox, a fair complexion lady in white dress & wearing white garland on her fore head; a pious Brahmin wearing white clothes-sandal & flowers-having properly fed & having received donations, reciting Mantras; a lady with a man or either of them having fruit in his or her hands- seen in front; a child saying something on his own; a beautiful person, person dressed in white clothes-wearing white garland, speaking sweetly if is found coming from front or right side during journey or at the time of entrance- it is an auspicious omen.
Homer, "The Odyssey"