RESURRECTING HEBREW (Nextbook. 219 pp. $21) by Ilan Stavans is reviewed in the Washington Post by Yehudah Mirsky. The review opens with a nice example:

In the Bible, the Book of Ezekiel begins with the heavens opening to reveal a stunning vision of God. Above the angels, astride a throne, like a fire encased in a frame, the prophet sees a kind of "hashmal."

This word is unique to Ezekiel's vision; in the entire Hebrew scriptures, it appears only there. Its exact meaning is uncertain, but the Talmud -- the vast compilation of Jewish law, lore and interpretation from the first centuries of the Common Era -- offers a powerful etymology: It comes from the phrase "Creatures of fire . . . keep their silence [Hebrew: HASHot] and murmur [u-meMALelot]." Thus, tradition holds that the mysterious hashmal is the aura surrounding the heavenly throne, woven from the breaths of angels, so sacred as scarcely to be audible, even to God.
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Yet on the streets of Israel today, hashmal is everywhere. As any child can tell you, it means "electricity."

More on the Hashmal here.