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.
1670s as a technical term in perspective drawing; more generally by 1706 as "the representation of anything drawn on a plane; a drawing, sketch, or diagram of any object," from French plan "ground plot of a building, map," literally "plane surface" (mid-16c.), from Latin planum "level or flat surface," noun use of adjective planus "level, flat" (from PIE root *pele- (2) "flat; to spread").
The notion is of "a drawing on a flat surface." A doublet of plain via a later, learned French form. The meaning "scheme of action, formulated scheme for the accomplishment of some object or attainment of an end" is by 1713.
1728, "make a plan of; put on paper the parts, dimensions, and methods of construction of," from plan (n.). By 1737 as "to scheme, to devise ways and means for (the doing of something)." Related: Planned; planning; plans. Planned economy is attested by 1931. Planned Parenthood (1942) formerly was Birth Control Federation of America.
late 15c., machinacion, "a plotting, an intrigue," from Old French machinacion "plot, conspiracy, scheming, intrigue" and directly from Latin machinationem (nominative machinatio) "device, contrivance, machination," noun of action from past-participle stem of machinari "to contrive skillfully, to design; to scheme, to plot," from machina "machine, engine; device trick" (see machine (n.)). Related: Machinations.
c. 1600, "a medicine made of secret ingredients by secret methods," but commonly "quack medicine," from Latin nostrum remedium "our remedy" (or some similar phrase), presumably indicating "prepared by the person offering it," from Latin nostrum, neuter of noster "our," from nos "we," from PIE *nes- (2); see us. In extended use, "a pet scheme for accomplishing something" (1749).