the.com/byproduct

The thing you weren't trying to make, which sometimes outlives the thing you were.

means A secondary result produced while making or doing something else, incidental to the main output.

from Straightforward compound from 'by-' (meaning secondary, off to the side, as in 'bystander' or 'byway') plus 'product.' It emerged with industrial-age manufacturing language, when factories and chemical processes started generating useful leftovers alongside their main output — sawdust from lumber mills, whey from cheesemaking — and English needed a plain word for 'the other thing that came out.'

origin story
Rubber was a tar-pit byproduct before it was useful
business model
Whey was dairy waste until it became protein powder
etymology
Coined to sound minor, often becomes the main event
side note
Viagra was a failed heart-drug byproduct
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