[ bahy-prod-uhkt ]
See 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. 2023

How to use by-product in a sentence

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

Scientific definitions for by-product


[ 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.

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