plan: [18] A plan is etymologically a design that has been ‘planted’ on the ground. Indeed in French, from which English acquired the word, it was originally plant, and was not altered to plan until the 16th century, under the influence of plan ‘flat’ (source of English plane ‘flat’). It was a derivative of the verb planter ‘plant’, and originally referred to the laying-out of the ground plan of a building. The metaphor seems first to have arisen in Italian pianta ‘ground plan’, a relative of plant, which prompted its development in French. => plant[plan etymology, plan origin, 英语词源]