by-product

noun

by-prod·​uct ˈbī-ˌprä-(ˌ)dəkt 

variants or byproduct

plural by-products or byproducts

1

: something produced in a usually industrial or biological process in addition to the principal product

Sulfured molasses is a by-product of sugar refining.

—Wayne Gisslen

Small amounts of amyloid beta are generated as an ordinary metabolic byproduct and are believed to do no harm, but larger amounts seem to be tied to Alzheimer's.

—January W. Payne

Meat by-products are parts other than meat, including organs, blood and bone …

—Amy D. Shojai

Among the most commonly occurring and thoroughly studied chlorination byproducts are trihalomethanes …

—Consumer Reports

2

: a secondary and sometimes unexpected or unintended result

Japan's success as an international exporter of manufactured goods is a by-product of the volatile trade among Japanese cities.

—Jane Jacobs

As investor confidence grows, overspending and overborrowing are typically byproducts of an aging bull market.

—Carolyn Bigda

One of the by-products of the information age is an increasing number of data formats.

—John Was

Synonyms of by-product

• derivation
• derivative
• derivate
• result
• product

Examples of by-product in a Sentence

hydrogen is one by-product of that chemical reaction

Recent Examples on the Web

Evidence remains mixed, and dreams could also be an experiential by-product of useful sleeping-brain activity, rather than an adaptation with its own job description. — New Atlas, 2 Nov. 2026

The material also reduced unwanted by-products and maintained stable performance throughout 12-hour trials. — Mrigakshi Dixit, Interesting Engineering, 27 Oct. 2026

Carbon dioxide in the atmosphere, a by-product of burning fossil fuels, has reached record-high levels (428 parts per million), as have other greenhouse gases such as methane (1,940 parts per billion) and nitrous oxide (340 parts per billion). — Jackie Flynn Mogensen, Scientific American, 14 Oct. 2026

But after six months of boiling, pulping, pressing and tinkering, a project in southeastern Turkey has turned roughly 300 kilograms of the agricultural by-product into sheets that can be stitched, folded, printed, woven and worn. — Alexandra Harrell, Footwear News, 23 Sep. 2026

Word History

First Known Use

1849, in the meaning defined at sense 1

Rhymes for by-product

• product

Kids Definition

by-product

noun

by-prod·​uct

ˈbī-ˌpräd-(ˌ)əkt

: a product or result produced in addition to the main product or result