Meaning

noun a series of steps to be carried out or goals to be accomplished

noun an arrangement scheme

noun scale drawing of a structure

originBorrowed from French plan (“flat surface, ground plot, map”), from Latin plānus. Some sources also argue for influence or alteration of French plant, from plantar, from Latin plantāre (“set, fix in place”). Compare plane, plain.

Etymology from Wiktionary, CC BY-SA 3.0