"Drift" originated in the early 14th century from Middle English, meaning "a being driven" (of snow, rain, or cattle).  Ut derives from Proto-Germanic driftiz (meaning "a driving" or "a herd"), untimately stemming from the Proto-Indo-European root dhreibh- ("to drive, push").  It is closely related to the verb drive and cognate with Old Norse drift (snowdrift) and Dutch drift (pasturage, drove).  Drift originally referred to things driven by nature (snow, wind, water) or moving cattle/herds. 

According to the Oxford English Dictionary (OED), the earliest known use of the noun drift in English is from before 1400 when it appears in Cursor Mundi, a 14th-century Northumbrian poem.  In the 1520s drift was used in a figurative sense to mean "aim, intention, or course" (e.g., "I catch your drift").  The verb drift is much later, with the earliest evidence in the OED dating from 1584.  In the 1610s drift was used as a transitive verb for driving things into heaps.  in the 1670s drift took on a nautical sense and was used to describe a ship's deviation from its course. 

Connecting character actions to "drift"—the gradual shift in their inner state, motivations, or relationships—is crucial for making stories feel authentic and engaging rather than forced. It translates internal emotional shifts into tangible "beats" or actions (e.g., avoiding eye contact, pacing) that show character growth and deepen empathy, ensuring characters feel human rather than stagnant.