Crossword Dictionary
plan
Have the will and intention (ahead of time) to carry out some action.
Synonyms: idea, plot, ploy, scheme, thought
Do you have an idea of what you want and have thought carefully and in detail about how to get it? Then you have a plan, a series of actions required to achieve a particular goal.
A plan can exist only in your head, or it can be a physical object, such as an architectural plan of a building, showing how you propose to build it. As a verb, plan means the act of thinking about how to achieve your aims. You might plan to apply to colleges soon. When you plan something, you're laying the seeds for a future result, so it's not surprising that plan comes from the early English word plante, meaning "seedling."
stratagem
noun
A plan or scheme, especially one used to outwit an opponent or achieve an end.
synonyms
plan, scheme, tactic, manoeuvre, course of action, line of action, ploy, gambit
examples:
‘Cunning plans, devious stratagems, state-of-the-art conventional forces, and legal and moral proscriptions, can all be helpful.’
‘If the hero wants to get the abducted girl home, and if the villain has discovered his plan, and means to subvert it, what stratagems will each employ in the last reel?’
‘It is not that the statute has a penumbral spirit which strikes down devices or stratagems designed to avoid its terms or exploit its loopholes.’