by-product

American  

[bahy-prod-uhkt] / ˈbaɪˌprɒd əkt /

noun

by-products plural

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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Other Word Forms

Noun Inflected Forms

• by-products
  plural

Etymology

Origin of by-product

First recorded in 1900–05

Example Sentences

It remains to be seen how long the price of fertiliser, a by-product of oil, will take to come down.

From BBC • Jun. 15, 2026

What may look like a fossil human tooth-picking groove could just as easily be the by-product of everyday chewing.

From Science Daily • Jun. 8, 2026

The government has provided funding to reactivate the Ensus bioethanol plant, which makes CO2 as a by-product, in order to shore up supplies of the gas.

From BBC • Apr. 25, 2026

Lynas however, says its by-product from rare earth refining produces a non-toxic, non-radioactive magnesium-rich gypsum and an iron phosphate with a very low level of naturally occurring radioactive material.

From Barron's • Apr. 22, 2026

Unconscious goblin guards covered the room’s floor in heaps, a by-product of the wolf’s entrance, most likely.

From "Half Upon a Time" by James Riley

Related Words

• outgrowth