Hip·par·chus (hĭ-pärkəs) fl. second century BC.
Greek astronomer who discovered the precession of the equinoxes, developed the techniques of trigonometry, and catalogued the positions of 850 stars in the earliest known star chart.
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Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
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