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

To spawn, salmon must swim hundreds or even thousands of miles upstream from the ocean, and in the Columbia River and its many tributaries, their path is obstructed by a massive network of hydroelectric dams. —Katherine J. Wu, The Atlantic, 7 Jan. 2026

Rescuers believe the pup did not travel over land but instead swam inland from the coast — likely entering the River Bure at Great Yarmouth and going upstream to Horning. —Moná Thomas, PEOPLE, 30 Dec. 2025

In a world first, scientists in Germany have successfully recorded tiny oil droplets hovering within a flowing liquid, and even drifting upstream against the current, defying typical fluid behavior. —Georgina Jedikovska, Interesting Engineering, 17 Dec. 2025

But, because kidney cancer occurs upstream from the bladder, any pain tends to be located further up the back to one side. —Colleen Doherty, Verywell Health, 29 Oct. 2025

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