The word "omen" comes from the Latin noun omen, which traces to the older Old Latin form osmen.  The Latin word omen, meaning "a foreboding, augury, or sign."  Historically, Romans used the word to describe naturally occurring phenomena (like birds flying in the sky) that were believed to predict future events, whether good or bad. 

According to the Oxford English Dictionary (OED), the noun "omen" was first recorded in English in 1582.  The noun is defined by the dictionary as "an event or phenomenon regarded as a portent of good or evil; a prophetic sign, an augury."  By comparison, the OED dates the verb form of "to omen" much later, to 1697, and the adjective "omened" (as in ill-omened) to 1685.  

Omens serve as powerful storytelling tools that build suspense, anchor narratives in cultural tradition, and guide character growth.  By acting as subtle harbingers of future events, they shape the pacing and emotional resonance of a story. 

The Core Functions of Omens:  
Foreshadowing: Omens prepare the audience for plot twists or tragedies, such as the famous warnings preceding Julius Caesar's assassination. This gives the narrative structural cohesion.  \|
Building Suspense: Whether an omen predicts good fortune or impending doom, it creates anticipation. The audience waits in tension to see how and when the prophecy will materialize.  
Character Development: How characters react to or interpret an omen reveals their core traits. A brave hero might face the omen head-on, while a tragic figure might succumb to denial or hubris.  
World-Building: Omens ground stories in specific mythologies or belief systems. By observing omens, writers showcase a society's values, fears, and understanding of the supernatural or natural world. 

Common Types of Omens in Fiction:  |
Natural Signs: Sudden changes in the weather, abnormal animal behavior (e.g., flocks of birds changing flight patterns), or eclipses.  |
Symbolic Objects: The sudden breaking of a family heirloom or the appearance of an unusual artifact.  
Dreams and Visions: Prophetic nightmares or hallucinations that offer cryptic clues to the protagonist. 
Oracles and Seers: NPCs or mystical entities that explicitly interpret the world's signs for the characters. 

Best Practices for Writers: 
Subvert Expectations: Omens become more engaging when they are misinterpreted by characters, creating unexpected obstacles or dramatic irony.  
Use Sparingly: Overloading a story with too many omens can dilute the stakes. They are most effective when kept mysterious and open to interpretation.  
Link to Theme: Ensure the omen aligns with the overarching theme of your story. An omen of war perfectly complements a grim, high-stakes fantasy.  

Don't forget Damien! 

Just the facts:

OMEN Definition & Meaning - Merriam-Webster

OMEN Synonyms: 30 Similar Words | Merriam-Webster Thesaurus

OMENS Synonyms: 28 Similar Words | Merriam-Webster Thesaurus

ABSIT OMEN Definition & Meaning - Merriam-Webster