upstream

adverb or adjective

up·​stream ˈəp-ˈstrēm How to pronounce upstream (audio)
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
3
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.

Examples of upstream in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
By that time, at least eight other firefighters were trying to save people upstream at the Riverview RV Park, where Trotter and Stark had been staying. — Abe Streep, ProPublica, 21 Oct. 2026 The models were swimming upstream through the crowd, the only people on the rooftop apparently going in the wrong direction. — Vogue, 8 Oct. 2026 Their landscape is already running, and switching costs are too high to treat every consolidation move upstream as an opportunity. — Girish Joshi, Forbes.com, 5 Oct. 2026 The Scott River, which flows out of mountain forests into a broad valley near the California-Oregon border, provides vital habitat for salmon that swim upstream from the ocean to spawn in the fall and winter. — Ian James, Los Angeles Times, 1 Oct. 2026 See All Example Sentences for upstream

Word History

First Known Use

1681, in the meaning defined at sense 1

Time Traveler
The first known use of upstream was in 1681

Rhymes for upstream

See All Rhymes for upstream

Browse Nearby Words

upstraight
upstream
upstreet
See all Nearby Words

Cite this Entry

“Upstream.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/upstream. Accessed 27 Oct. 2026.

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Kids Definition

upstream

adverb or adjective
up·​stream ˈəp-ˈstrēm How to pronounce upstream (audio)
: at or toward the beginning of a stream : against the current
salmon swimming upstream

Medical Definition

upstream

adverb or adjective
up·​stream ˈəp-ˈstrēm How to pronounce upstream (audio)
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
2
: 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
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