upstream
UK: ˌʌpˈstriːm | US: ˈʌpˌstrim
adj. situated or moving in the direction opposite to the flow of a stream or current
adv. in or toward the source of a stream or current
adj. (figurative) relating to earlier stages in a process or supply chain
The word "upstream" combines "up" (Old English "ūp," meaning "to a higher position") and "stream" (Old English "strēam," meaning "flowing water"). It literally describes movement against the current of a river, later extended metaphorically to processes (e.g., supply chains or data flow). The logic is spatial: "up" implies opposition to the natural direction of the stream.
Salmon swim upstream to spawn.
The factory is located upstream from the city’s water supply.
Upstream investments in research can reduce downstream costs.
The team traced the error to an upstream data source.
Pollution upstream affects ecosystems miles downstream.