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

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

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

In 2017, when the Oroville Dam’s spillway came apart upstream, the fields sat beneath the Feather River for months, and the Lundbergs farmed nothing on the land. — Sean MacAday, Sacbee.com, 20 Sep. 2026

Word History

First Known Use

1681, in the meaning defined at sense 1

Rhymes for upstream

• abeam
• airstream
• bloodstream
• daydream
• downstream
• esteem
• extreme
• grapheme
• hakim
• hornbeam
• lexeme
• mainstream

Kids 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

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