The act of designing, planning, or marking out; a design or plan itself, especially when completed.
From Old French 'designment' and Latin 'designamentum,' derived from 'designare' (to mark out, appoint). This noun form developed to name the action and result of design work.
This is a medieval and Renaissance word you'd find in guild documents and architectural contracts—'the designment of the cathedral was approved by the bishop.' It sounds formal because it was: official documentation of planned work.
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