1An incidental or secondary product made in the manufacture or synthesis of something else.
‘zinc is a by-product of the glazing process’
‘Further down the valley on the old soda ash beds, wild orchids bloom on the alkaline soil, a by-product of soda manufacture.’
‘The process of drilling for oil produces toxic by-products - drilling mud and poisonous waste water, which get dumped into the ocean.’
‘Sugar cane fiber, a by-product of sugar manufacturing, can be made into paper.’
‘One of the most significant is carbon dioxide, a by-product of burning fossil fuels such as oil, petrol and coal.’
‘Although these trace minerals are present in grains and by-products, iron, zinc, copper, selenium, and iodine need to be supplemented.’
‘In the case of yeast's metabolic activity in six-carbon sugar solutions such as grape juice, the three main by-products are water, ethanol, and carbon dioxide.’
‘Vegans won't eat any animal products or by-products at all, which is weird.’
‘The manufacture of chemical weapons produces chemical by-products and chemical contamination.’
‘Ancient Greeks and Romans observed it in its potassium salt form as a by-product in the production of wine.’
‘We are not aware of any silver mutual fund since most silver is produced as a by-product of other metals such as copper.’
‘Yaks provide wool and milk by-products such as butter, which are sold or bartered for grain.’
‘Tons of straw are produced each year as a by-product of grain production.’
‘Microsilica or silica fume is a by-product in the manufacture of silicon and ferrosilicon alloys.’
‘Lactic acid is a by-product that's produced in the muscle fibres when they can't keep up with the energy demands.’
‘Picric acid is a by-product from the manufacturing of explosives.’
‘In Ireland it is produced as a by-product of the drugs industry.’
‘Many materials are already in use or in development, including wood waste, sewage cake, agricultural by-products and waste from the food processing industry.’
‘Only methanol is required as fuel, and the by-products are heat, water, and carbon dioxide.’
‘Cooking gas, gasoline and diesel are by-products of crude oil.’
‘But trees naturally absorb CO2 and produce in its place useful by-products: oxygen and wood.’