Etymology
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log in (v.)
verbal phrase, 1963 in the computing sense, from log (v.2) + in (adv.).
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dead reckoning (n.)

"ascertaining of the position of a ship by measurement of the distance run" (without observation of heavenly bodies), 1610s, perhaps from nautical abbreviation ded. ("deduced") in log books, but it also fits dead (adj.) in the sense of "unrelieved, absolute."

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