Also bye-. [f. BY- 4, 5 + PRODUCT.] A secondary product; a substance of more or less value obtained in the course of a specific process, though not its primary object.
1857. Eliza Acton, Eng. Bread-bk., II. 95–6. German yeast … in many distilleries forms an important by-product.
1876. M. Foster, Physiol. (1879), App. 663. When any proteid is digested with pepsin … a bye-product makes its appearance.
1882. Standard, 24 Aug. By-products of gas manufacture.
