The sense "program of action" first is attested 1640s. Unfavorable overtones (selfish, devious) began to creep in early 18c. Meaning "complex unity of coordinated component elements" is from 1736. Color scheme is attested from 1884.
Extended sense of "brief account" is from 1660s; meaning "short play or performance, usually comic" is from 1789. Sketch-book recorded from 1820. German Skizze, French esquisse, Spanish esquicio are likewise from Italian schizzo.
c. 1600, "to lay plots, intrigue," a back-formation from machination, or else from Latin machinatus, past participle of machinari "to contrive skillfully; to design, scheme, plot." Transitive sense of "to plan, contrive, form (a plot, scheme, etc.)" also is from c. 1600. Related: Machinated; machinating; machinator.
c. 1400, projecte, "a plan, draft, scheme, design," from Medieval Latin proiectum "something thrown forth," noun use of neuter of Latin proiectus, past participle of proicere "stretch out, thrust out, throw forth," from pro- "forward" (see pro-) + combining form of iacere (past participle iactus) "to throw" (from PIE root *ye- "to throw, impel").
Meaning "scheme, proposal, mental plan" is from c. 1600. Meaning "group of government-subsidized low-rent apartment buildings" is recorded from 1935, American English, short for housing project (1932). Related: Projects. Project manager is attested from 1913.