plot [OE] The first meaning of plot was ‘a small piece of ground’. The sense ‘secret plan’ dates from the late 16th century and was probably developed out of the sense ‘map, plan’ influenced by Old French complot ‘dense crowd, secret project’. Guy Fawkes’ Gunpowder Plot of 1605 is thought to have spread the use of this sense. From another sense of plot, ‘the main sequence of events in a play, novel, or film’, comes the expression the plot thickens. The person to thank for it is George Villiers, the 2nd Duke of Buckingham, whose satirical drama The Rehearsal (1671) includes the line ‘Ay, now the plot thickens very much upon us.’