proof plane

noun

: a small metal disk attached to an insulating handle, used in testing the nature of the electrification of a body

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Dictionary Entries Near proof plane

proof paper

proof plane

proof positive

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“Proof plane.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/proof%20plane. Accessed 25 Mar. 2023.

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