byproduct
UK: ˈbaɪˌprɒdʌkt | US: ˈbaɪˌprɑːdʌkt
n. a secondary or incidental product resulting from a manufacturing process or chemical reaction
n. an unintended but inevitable result of an action or situation
The word "byproduct" combines "by," meaning "secondary" or "incidental," with "product," referring to something created. Originating in the early 19th century, it reflects industrial processes where primary outputs (e.g., refined metals) often generate unintended secondary materials (e.g., slag). Over time, it expanded metaphorically to describe unintended consequences in non-industrial contexts.
Sulfur dioxide is a harmful byproduct of burning coal.
The new policy had the unintended byproduct of increasing unemployment.
Cheese makers often sell whey as a profitable byproduct.
Happiness was a welcome byproduct of her volunteer work.
The factory recycles its byproducts to reduce waste.