The word "context" comes from Latin contextus, the past participle of contexere (to weave together).  it derives from the roots con- ("together") and texere ("to weave"), literally meaning "to weave together," signifying the interconnected elements forming a whole, like words in a text or circumstances surrounding an event, crucial for understanding its meaning.  Its use evolved from describing textual composition to encompassing broader situations, settings, or background information that gives clarity and frames interpretation. 

According to the Oxford English Dictionary (OED), the noun context appeared in English during the Middle English period (1150-1500), with the earliest evidence found before 1475 in R. Higden's Polychronicon.  The adjective form, context, emerged slightly later, around 1541, with OED evidence from Robert Copland.  The verb form emerged in the early 1600s, with evidence from Owen Felltham.  

Context in writing refers to the surrounding circumstances -- like time, place, culture, audience, and purpose -- that give meaning and clarity to a text, helping readers understand the author's intent, character, motivations, or unfamiliar items, essentially providing the "why" and "where" behind the "what" of the words.  It influences style, tone, and content, making writing relevant and impactful by bridging the gap between writer and reader, ensuring the message is received as intended. 

Manipulating context is called spin.

Just the facts:

CONTEXT Definition & Meaning - Merriam-Webster

CONTEXT Synonyms: 26 Similar Words | Merriam-Webster Thesaurus

IN CONTEXT Definition & Meaning - Merriam-Webster