upstream
adverb or adjective
up·stream
ˈəp-ˈstrēm 
1
: in the direction opposite to the flow of a stream
2
: in or to a position within the production stream closer to manufacturing processes
make most of its money upstream, selling cheap crude … to refineries—
John Quirt
John Quirt3
biochemistry
: toward the beginning of a series of cellular processes : preceding a linked molecular event occurring in a sequence
Many signaling pathways possess intrinsic negative feedback by which a downstream event in a pathway turns off an upstream event.—Harvey Lodish et al.
Harvey Lodish et al.Examples of upstream in a Sentence
Recent Examples on the Web
Suckers were spawning upstream, and the trout kept coming into the pool in schools to feed on the drifting spawn.
—Robeson Bailey, Outdoor Life, 11 June 2025
Worthy shares that the victim was found in a circular movement of water against a rock face, and police had to approach upstream to recover the toddler.
—David Chiu, People.com, 10 June 2025
The fishing industry depends on fall-run Chinook, which migrate upstream to spawn from July through December.
—Ian James, Los Angeles Times, 6 June 2025
State officials are accepting comments on the environmental impacts of a project proposed by 3M Corp. to collect surface water upstream of a dump in Oakdale in order to reduce polyfluoroalkyl substances (PFAS) in stormwater discharge from the site.
—Mary Divine, Twin Cities, 1 June 2025
See All Example Sentences for upstream
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Robeson Bailey, Outdoor Life, 11 June 2025
Worthy shares that the victim was found in a circular movement of water against a rock face, and police had to approach upstream to recover the toddler.
—David Chiu, People.com, 10 June 2025
The fishing industry depends on fall-run Chinook, which migrate upstream to spawn from July through December.
—Ian James, Los Angeles Times, 6 June 2025
State officials are accepting comments on the environmental impacts of a project proposed by 3M Corp. to collect surface water upstream of a dump in Oakdale in order to reduce polyfluoroalkyl substances (PFAS) in stormwater discharge from the site.
—Mary Divine, Twin Cities, 1 June 2025
See All Example Sentences for upstream
Cite this Entry
“Upstream.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/upstream. Accessed 17 Jun. 2025.
Copy CitationKids Definition
upstream
adverb or adjective
up·stream
ˈəp-ˈstrēm
: at or toward the beginning of a stream : against the current
salmon swimming upstream
Medical Definition
upstream
adverb or adjective
up·stream
ˈəp-ˈstrēm
1
: in a direction along a molecule of DNA or RNA opposite to that in which transcription and translation take place and toward the end having a phosphate group attached to the position labeled 5′ in the terminal nucleotide
… stretches of DNA upstream of genes—are known as promoters.—Matt Ridley, Time
compare downstream sense 1
Matt Ridley, Time2
: toward the beginning of series of cellular processes : preceding a linked molecular event occurring in a sequence
It's equally important to focus on additional mechanisms that are upstream of amyloid formation and mechanisms downstream that are involved in the actual degenerative processes within neurons.—Marc Tessier-Lavigne, quoted in Science
Marc Tessier-Lavigne, quoted in ScienceLove words? Need even more definitions?
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