The word mourning traces back to the Old English verb murnan (to feel sorrow, bemoan, or be anxious about).  It stems from the Proto-Germanic murnaną and ultimately derives from the Proto-Indo-European root *(s)mer-, meaning "to remember".  During the Middle English period, the verbal suffix -ing was added to mourn to describe the act, state, or outward expression of grief (such as wearing black).  

According to the Oxford English Dictionary (OED), the word mourning (as both a noun and an adjective) was first used in the Old English period (pre-1150).  It stems from the Old English word murnung (meaning complaint, grief, or lamenting) and is the verbal noun derived from the root word murnan (to grieve or be anxious).  Because "mourning" has multiple senses in the OED, the dictionary categorizes its usage into specific historical milestones: Earliest General Use (Sorrow/Lamentation): Dates to the Old English period (pre-1150).  Earliest Specific Use (Attire): The concept of customary "mourning black" apparel has its earliest evidence in Geoffrey Chaucer's Middle English texts from before 1425.  Specific Meaning (Sorrow/Care for an Animal): A distinct definition tracking the word's physical caretaking sense is cited from around 1465.  Interestingly, the related verb mourn was actually back-formed after the noun, with the OED citing its earliest use much later, around 1580.  

Mourning in storytelling anchors emotional stakes by exposing a character's deepest vulnerabilities.  It builds reader empathy, provides necessary catharsis, and propels character development. By confronting loss, narratives transform abstract pain into relatable meaning, demonstrating how resilience is forged through hardship. 

The Core Pillars of Mourning in Narrative:  
Establishes Emotional Stakes: Witnessing a character's grief makes the stakes feel real. When an author explores loss, it proves to the audience that the bonds between characters matter, raising the emotional tension for whatever conflicts come next. 
Drives Character Growth: Grief forces characters to change. A story that allows a protagonist to mourn authentically—moving from denial and anger to acceptance—creates deeply satisfying character arcs rather than having them bounce back instantly from trauma. 
Builds Reader Empathy: Universal experiences of loss and heartbreak connect audiences directly to the narrative. Seeing a character process their pain helps readers make sense of their own emotions. 
Creates Catharsis: Navigating grief alongside a character delivers a powerful, emotional release and highlights that confronting such difficult emotions allows everyone to feel seen and validated in their shared humanity. 
Defines the Antagonist: In contrast to heroes who process their grief constructively, villains are often defined by unresolved, festering mourning. Their inability to process a tragedy provides a compelling psychological explanation for their destructive actions.  
Preserves Legacy: Mourning in a story is not just about the pain of an ending; it acts as a mechanism for the hero to honor the past. By sharing the stories and values of the fallen, characters ensure that what was lost continues to impact the ongoing narrative.