What does byproduct mean?
A byproduct is something produced incidentally in the course of making something else — either a physical substance left over from manufacturing or, figuratively, an unplanned consequence of an activity. In industry, byproducts range from valuable commodities like whey, glycerin, and blast-furnace slag to troublesome waste that must be disposed of safely. In everyday and academic language, the term extends to abstract outcomes: congestion can be described as a byproduct of urbanization, or anxiety as a byproduct of modern work culture. The word is written both as 'byproduct' and as the hyphenated 'by-product', with the closed form now dominant in American English and gaining ground generally. Neutral in tone, it emphasizes that the result was secondary or incidental rather than intended — which makes it especially useful for discussing unintended consequences, whether those turn out to be profitable discoveries or environmental problems worth solving.
nounA secondary or incidental product made during the manufacture of something else; more broadly, any unintended but inevitable result of an activity or process.
- A secondary substance produced incidentally during the manufacture of a primary product.
- An incidental or unintended result of an activity, process, or situation.
"Whey, once discarded as a byproduct of cheese-making, is now prized as a protein source."
"The refinery sells its byproducts rather than burning them off."
"Urban sprawl is often a byproduct of economic growth."
Regular plural; the hyphenated variant 'by-products' appears mainly in formal British texts.
"The plant recycles nearly all of its byproducts into animal feed."
Some of history's most valuable products started life as trash: margarine, Vaseline, and even whey protein were all once mere byproducts someone decided not to waste.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of byproduct
Byproduct is a compound of the English prefix 'by-', meaning 'secondary' or 'incidental', and 'product', from Latin 'productum', the neuter past participle of 'producere', meaning 'to bring forth or draw out'. The hyphenated form 'by-product' arose in English during the nineteenth century alongside industrialization, when manufacturers began systematically identifying and monetizing secondary outputs; the closed spelling 'byproduct' later became standard, particularly in American usage. Its relatives include 'produce', 'production', and 'productive', all descending from the same Latin root.
Related word forms
How byproduct is actually used
Both 'byproduct' and 'by-product' are accepted; the unhyphenated form dominates in American English and increasingly elsewhere. The word carries no strong positive or negative connotation — it can describe valuable secondary products or unwanted waste, depending on context.
Easily confused with byproduct
Not truly a different word — 'by-product' is simply the older hyphenated spelling of the same noun, still common in formal British writing, while 'byproduct' is the unhyphenated form standard in American usage.