1650s, "unroll, unfold" (a sense now obsolete), from French développer. It replaced earlier English disvelop (1590s, from French desveloper); both French words are from Old French desveloper, desvoleper, desvoloper "unwrap, unfurl, unveil; reveal the meaning of, explain," from des- "undo" (see dis-) + voloper "wrap up," which is of uncertain origin, possibly Celtic or Germanic.
The modern uses are figurative and emerged in English 18c. and after: Transitive meaning "unfold more fully, bring out the potential in" is by 1750; intransitive sense of "come gradually into existence or operation" is by 1793; that of "advance from one stage to another toward a finished state" is by 1843. The intransitive meaning "become known, come to light" is by 1864, American English.
The photographic sense "induce the chemical changes necessary to cause a latent picture or image to become visible" is from 1845; the real estate sense of "convert land to practical or profitable use" is by 1865. Related: Developed; developing.Developing as an adjective in reference to poor or primitive countries or nations that are advancing in economic, industrial, and social conditions is by 1960.
1833, "one who or that which develops," agent noun from develop. Photography use in reference to the chemical bath used to bring out the latent image is attested from 1869; meaning "speculative builder" is by 1938.
1756, "a gradual unfolding, a full working out or disclosure of the details of something;" see develop + -ment. Meaning "the internal process of expanding and growing" is by 1796; sense of "advancement through progressive stages" is by 1836.
Of property, with a sense of "a bringing out of the latent possibilities" for use or profit, from 1885 (Pickering's glossary of Americanisms, 1816, has betterments "The improvements made on new lands, by cultivation, and the erection of buildings, &c."). Meaning "state of economic advancement" is from 1902.
1844, "to act as an optimist, take the most hopeful view of a matter," a back-formation from optimist. Meaning "to make the most of, develop to the utmost" is attested by 1857. Related: Optimized; optimizing.