1670s as a technical term in perspective drawing; 1706 as "drawing, sketch, or diagram of any object," from French plan "ground plan, map," literally "plane surface" (mid-16c.), from Latin planum "level or flat surface," noun use of adjective planus "level, flat" (see plane, n.1). The notion is of "a drawing on a flat surface." Meaning "scheme of action, design" is first recorded 1706, possibly influenced by French planter "to plant," from Italian planta "ground plan."

1728, "make a plan of," from plan, n.. Related: Planned; planning; plans. Planned economy is attested from 1931. Planned Parenthood (1942) formerly was Birth Control Federation of America.