[bahy-prod-uh kt]
See more synonyms for by-product on
  1. a secondary or incidental product, as in a process of manufacture.
  2. the result of another action, often unforeseen or unintended.

Origin of by-product

First recorded in 1900–05 Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for by-product

Contemporary Examples of by-product

Historical Examples of by-product

  • With regard to leather, this material is, under present conditions, a 'by-product.'

    No Animal Food

    Rupert H. Wheldon

  • Nor is there any satisfactory application of this by-product as yet evolved.

  • As silver is now obtained largely as a by-product, there is almost no waste.

    Checking the Waste

    Mary Huston Gregory

  • It is not a by-product, but an essential part of the animal's equipment.

    The Story of the Mind

    James Mark Baldwin

  • It is prepared commercially as a by-product in the steel-plate mills.

British Dictionary definitions for by-product


  1. a secondary or incidental product of a manufacturing process
  2. a side effect
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for by-product

also byproduct; 1857, from by + product.

Online Etymology Dictionary, © 2010 Douglas Harper

by-product in Science


  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.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.