byproduct
n.something that is made or happens while you are trying to make or do something else. It is an extra result that you did not plan for.
n.a secondary or incidental product resulting from a manufacturing process or chemical reaction; by extension, any unintended consequence of an action.
“Heat is a byproduct of using this machine.”
“The new highway was built for travel, but a positive byproduct was the growth of local businesses along the route.”
“While the software was designed purely for data encryption, its high processing speed became a valuable byproduct that attracted interest from the gaming industry.”
Often used with the preposition 'of' to indicate the primary process or source.
“The only byproduct of the setup is pure water – which Lorde and other artists who perform there will be invited to sample at the end of their gigs.”
“Mendes compares the action of the microbiome, a collection of microorganisms and their byproducts, to that of the human immune system.”
From by- + product.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.