The Collaborative International Dictionary of English v.0.48:

Plan \Plan\, v. t. [imp. & p. p. Planned; p. pr. & vb. n.
   Planning.]
   1. To form a delineation of; to draught; to represent, as by
      a diagram.
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   2. To scheme; to devise; to contrive; to form in design; as,
      to plan the conquest of a country.
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            Even in penance, planning sins anew.  --Goldsmith.
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The Collaborative International Dictionary of English v.0.48:

Plan \Plan\, n. [F., fr. L. planus flat, level. See Plain, a.]
   1. A draught or form; properly, a representation drawn on a
      plane, as a map or a chart; especially, a top view, as of
      a machine, or the representation or delineation of a
      horizontal section of anything, as of a building; a
      graphic representation; a diagram.
      [1913 Webster]

   2. A scheme devised; a method of action or procedure
      expressed or described in language; a project; as, the
      plan of a constitution; the plan of an expedition.
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            God's plans like lines pure and white unfold. --M.
                                                  R. Smith.
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   3. A method; a way of procedure; a custom.
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            The simple plan,
            That they should take who have the power,
            And they should keep who can.         --Wordsworth.
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   Body plan, Floor plan, etc. See under Body, Floor,
      etc.
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   Syn: Scheme; draught; delineation; plot; sketch; project;
        design; contrivance; device. See Scheme.
        [1913 Webster]

WordNet (r) 3.0 (2006):

plan
    n 1: a series of steps to be carried out or goals to be
         accomplished; "they drew up a six-step plan"; "they
         discussed plans for a new bond issue" [syn: plan,
         program, programme]
    2: an arrangement scheme; "the awkward design of the keyboard
       made operation difficult"; "it was an excellent design for
       living"; "a plan for seating guests" [syn: design, plan]
    3: scale drawing of a structure; "the plans for City Hall were
       on file" [syn: plan, architectural plan]
    v 1: have the will and intention to carry out some action; "He
         plans to be in graduate school next year"; "The rebels had
         planned turmoil and confusion" [syn: plan, be after]
    2: make plans for something; "He is planning a trip with his
       family"
    3: make or work out a plan for; devise; "They contrived to
       murder their boss"; "design a new sales strategy"; "plan an
       attack" [syn: plan, project, contrive, design]
    4: make a design of; plan out in systematic, often graphic form;
       "design a better mousetrap"; "plan the new wing of the
       museum" [syn: design, plan]

The Free On-line Dictionary of Computing (19 January 2023):

PLAN

    Programming LANguage Nineteen hundred.

   The assembly language for ICL 1900 series computers.

   (1995-03-21)


The Devil's Dictionary (1881-1906):

PLAN, v.t.  To bother about the best method of accomplishing an
accidental result.