The word alignment (noun) is  derived from align (verb), primarily originating from 18th-century French alignement, which comes from aligner ("to place in a line").  It combines the prefix a-  ("to") and the word ligne  ("line").  Aligner is derived from the Old French alignier, which combined the prefix a- (from Latin ad- ("to") + lignier ("to line").  The original meaning pertains to arranging objects or troops in a straight line, as seen in the French military term aligner.  The metaphorical sense of political or social "alignment" (bringing people into agreement or alliance) emerged much later, with the international political sense attested in the 1930s.  

According to the Oxford English Dictionary (OED), the noun alignment (or its early variant alinement) is first attested in English in the mid-18th century, with the earliest evidence dating to 1742.  The 1742 usage appears in a translation of a French work by J. Martyn and E. Chambers.  While "alignment" is the standard form now, "alinement" was a common spelling in the 18th and 19th centuries.  This ultimately stems from the Latin lineare ("to reduce to a straight line" or "make straight"), which is derived from linea ("line" or "flax").   Align (verb) appeared in English in the early 15th century (1425). (initially in senses related to ranging, sometimes with complex definitions like "copulate" regarding animals).  

Character alignment—positioning characters along moral (good/evil) and social (lawful/chaotic) axes—is vital for building consistent, believable, and compelling stories. It helps define character motivations, shapes the plot, generates conflict, and fosters audience empathy by ensuring characters' actions align with their established personalities, making them memorable and relatable. 

Key Aspects of Character Alignment: 
Driving the Plot: Characters are the engine of a story. Their decisions, rooted in their alignment, naturally propel the narrative, ensuring actions feel justified rather than random or forced. 
Building Cohesion: Alignment ensures a character's actions, goals, and voice are consistent throughout the story, making them feel real and multi-dimensional rather than one-dimensional. 
Creating Conflict: By placing characters with opposing outlooks (e.g., lawful good vs. chaotic evil) together, it generates compelling tension and drama. 
Audience Connection: Well-aligned, consistent characters allow readers to empathize with their struggles and triumphs, engaging them emotionally.