meh₁-
“to measure”measure, mark, time
Root for measuring, yielding Latin metiri, Greek metron, English measure, moon, month.
Discussion
The root *meh₁- carried the meaning "to measure" and became one of the foundational formations underlying science, timekeeping, and medicine. Latin mētīrī ("to measure") generated measure, meter, dimension, and immense ("that which cannot be measured"). Greek metron ("measure") gave metric, geometry ("earth-measuring"), symmetry ("measuring together"), and the entire apparatus of quantitative reasoning. One of the most significant derivatives is English moon, from *meh₁n̥s- meaning "the measurer" — early Indo-European peoples reckoned time by lunar cycles, and month itself derives from the same formation. The medical vocabulary traces back through Latin medicus, "physician," likely from "one who measures out remedies," connecting the healer's art to the precision of dosage. Rix (LIV² 424) establishes the verbal base. The root charts a remarkable arc from the simple act of comparing quantities to the measurement of time by celestial bodies to the measured wisdom of the physician.
Notes
Pokorny 703-704. English measure, meter, moon, month, dimension, immense.