Extortion or theft of money through threats or intimidation; also, a thorough search or inspection; or a trial period to test how something works.
From the verb phrase 'shake down' (to shake until something falls out), originally referring to shaking money from someone, then expanding to mean thorough searching and testing.
A 'shakedown cruise' is when a newly-built ship takes its first voyage to find and fix problems—NASA uses this term for new spacecraft, testing systems before they go to space where you can't repair things.
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