English Reference
adjective · adverb · verb

upstream

adj. · adv. · v.
US /ˈəpˈstɹim/ UK /ʌpstɹˈiːm/ up·stream

  1. 01 B2 Upper Intermediate

    adj.located or moving in the opposite direction to the way a river or stream flows.

    adj.situated or moving in a direction contrary to the flow of a current or stream.

    Simple

    The salmon swim upstream for many miles to reach their spawning grounds.

    In context

    The researchers took water samples from an upstream location to ensure the data wasn't contaminated by the factory's waste pipe further down.

    upriver
  2. 02 C1 Advanced AcademicTechnical

    adj.happening at an earlier stage in a process, such as the start of a production line.

    adj.relating to the earlier stages of a process, particularly in industrial production, supply chains, or biological pathways.

    Simple

    The company is investing in upstream activities like oil exploration and drilling.

    In context

    By addressing the problem at an upstream stage of the manufacturing process, the engineers prevented a series of defects in the final product.

    Usage

    Often used in business to refer to the extraction of raw materials.

  3. 03 B2 Upper Intermediate

    adv.moving against the current of a river.

    adv.in a direction against the flow of a stream or current.

    Simple

    It is much harder to row upstream than it is to go with the current.

    In context

    The barge struggled to move upstream against the heavy spring floods, requiring additional tugboats to maintain its course.

    upriver
  4. 04 C1 Advanced Technical Computing

    v.to send a software update back to the original creators so they can include it in the main version.

    v.to submit a software patch or feature to the original developers or maintainers of a project for inclusion in the primary source code.

    Simple

    The developer decided to upstream her bug fixes to the main Linux project.

    In context

    The team worked hard to upstream their security patches, ensuring that the entire community would benefit from the improved code in the next release.

Dawadi, the headteacher at Tribhuvan Trishuli secondary school in Nuwakot, which has 1,600 pupils, said he had received four warnings from different people within minutes, including one from Betrawati, a town directly upstream.

The Guardian· 30 Aug 2026

Further upstream, the character of the river changes.

Phys.org· 14 Aug 2026

From up- + stream.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Level B2 · Upper Intermediate
Frequency Frequent
Updated