# upstream

/ˈəpˈstɹim/ (US) · /ʌpstɹˈiːm/ (UK)

Source: https://englishreference.com/word/upstream
Updated: 2026-06-20

## Senses

### 1. against the water flow

adjective · CEFR B2

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

For teachers: situated or moving in a direction contrary to the flow of a current or stream.

- The salmon swim upstream for many miles to reach their spawning grounds.
- The researchers took water samples from an upstream location to ensure the data wasn't contaminated by the factory's waste pipe further down.

### 2. earlier in a process

adjective · CEFR C1 · Academic · Technical

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

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

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

adverb · CEFR B2

moving against the current of a river.

For teachers: in a direction against the flow of a stream or current.

- It is much harder to row upstream than it is to go with the current.
- The barge struggled to move upstream against the heavy spring floods, requiring additional tugboats to maintain its course.

### 4. software development

verb · CEFR C1 · Technical

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

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

- The developer decided to upstream her bug fixes to the main Linux project.
- The team worked hard to upstream their security patches, ensuring that the entire community would benefit from the improved code in the next release.

## Examples

- The salmon swim upstream to lay their eggs.
- The environmental agency took water samples from the upstream section of the river to find the source of the pollution.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.