עָלַם
Hebrew root verb meaning "to hide" or "to conceal." Lapide cites it as the etymological root of *olam* ("eternal"), explaining that "eternal" in Hebrew signifies something whose end is hidden or concealed.
Commentary on the Pentateuch of Moses
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Canons Bearing a Torch Before the Pentateuch
— Root of olam, explaining the etymology of "eternal" as "hidden"
"For the root alam means to hide or conceal"