【Plan】 ,  【design】 ,  【plot】 ,  【scheme】 ,  【project】 , as nouns, denote a proposed method of doing or making something or of achieving a given end, and as verbs, to devise such a method.

【Plan】 , in its widest sense, regularly implies mental formulation of the method. In a narrower sense, the terms may imply a graphic representation of such a method (as by a mechanical drawing, a chart, a sketch, or a layout).

【Design】  (see also INTENTION ) adds to  【plan】 an emphasis on intention (as artistic or divine intention) in the disposition of individual members or details, often thereby suggesting a definite pattern; since it is used frequently in reference to a completed work, it often implies reference to the degree in which order, harmony, or integrity have been achieved in spite of diversity in the parts, or in which there is the beauty that results from unity in variety.

【Plot】  (see also  【PLOT】 2 ) ( SKETCH ) usually connotes a laying out in clearly distinguished and carefully proportioned sections or divisions, and attention to proper placing and due relation of the parts, and to scale. It is found chiefly in technical use, such as that of surveying, where it suggests a ground 【plan】 or in literature, where it refers to a fundamental 【design】 which the action of a drama or narrative follows.

【Scheme】 has nearly lost its early implication of a diagram except in some technical senses where it suggests tabulation more often than outline drawing. Nevertheless, the word often suggests, more than  【plan】 does, system and careful choice or ordering of details. The terms often connote, singly or in combination, self-delusion, craftiness, or self-seeking on the part of the agent.

【Project】  comes close to  【scheme】 except in its connotations. Sometimes it suggests enterprise; sometimes, imaginative scope or vision; sometimes, mere extensiveness.