The quality of being exact; great precision, accuracy, and carefulness in every detail.
From Latin exactitudo (from exactus 'precise' + -itudo, abstract noun suffix). Entered English in the 17th century as a formal term for the virtue of precision.
Scientists obsess over exactitude because even microscopic errors in measurement can invalidate years of research—it's the reason we have constants like gravitational acceleration defined to dozens of decimal places.
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