by-product

American  

[bahy-prod-uhkt] / ˈbaɪˌprɒd əkt /

noun

1. a secondary or incidental product, as in a process of manufacture.

2. the result of another action, often unforeseen or unintended.

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by-product British  

noun

1. a secondary or incidental product of a manufacturing process

2. a side effect

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by-product Scientific  

/ bī′prŏd′əkt /

1. Something produced in the process of making something else. When plants produce carbohydrates by photosynthesis, oxygen is released as a by-product. Asphalt and paraffin are by-products of the process of refining crude oil into gasoline.

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Etymology

Origin of by-product

First recorded in 1900–05

Example Sentences

Existing by-product is already stored in a permanent disposal facility "constructed and managed to ensure the material does not impact on the surrounding environment," the company said.

From Barron's • Apr. 22, 2026

Through it all, however, West struggled with depression and a sense of self-loathing, and had trouble with intimacy, much of it a by-product of a hardscrabble childhood in West Virginia with a domineering father.

From Los Angeles Times • Apr. 14, 2026

This underused by-product has shown strong potential for enriching bread with protein, fiber, and antioxidant compounds.

From Science Daily • Feb. 8, 2026

But it is difficult to quickly increase silver supplies as the majority of global output is a by-product from mines that mainly extract other metals like lead, copper or gold.

From BBC • Dec. 10, 2025

The modern idea of laws of nature is a by-product of Descartes’ philosophy, for Descartes was the first person to treat the laws of nature as being what knowledge of nature was all about.

From "The Invention of Science" by David Wootton

Related Words

• outgrowth