chasmal and amber

The Hebrew word for "electricity" is chashmal חשמל. That is originally a biblical word, only appearing three times (all in the book of Yechezkel). Certainly at that time it didn't mean electricity. So how did the modern meaning come about?

These are the three verses:

וָאֵרֶא וְהִנֵּה רוּחַ סְעָרָה בָּאָה מִן־הַצָּפוֹן עָנָן גָּדוֹל וְאֵשׁ מִתְלַקַּחַת וְנֹגַהּ לוֹ סָבִיב וּמִתּוֹכָהּ כְּעֵין הַחַשְׁמַל מִתּוֹךְ הָאֵשׁ׃

I looked, and lo, a stormy wind came sweeping out of the north—a huge cloud and flashing fire, surrounded by a radiance; and in the center of it, in the center of the fire, a gleam as of amber. (1:4)

וָאֵרֶא כְּעֵין חַשְׁמַל כְּמַרְאֵה־אֵשׁ בֵּית־לָהּ סָבִיב מִמַּרְאֵה מָתְנָיו וּלְמָעְלָה וּמִמַּרְאֵה מָתְנָיו וּלְמַטָּה רָאִיתִי כְּמַרְאֵה־אֵשׁ וְנֹגַהּ לוֹ סָבִיב׃

From what appeared as his loins up, I saw a gleam as of amber—what looked like a fire encased in a frame; and from what appeared as his loins down, I saw what looked like fire. There was a radiance all about him. (1:27)

וָאֶרְאֶה וְהִנֵּה דְמוּת כְּמַרְאֵה־אֵשׁ מִמַּרְאֵה מָתְנָיו וּלְמַטָּה אֵשׁ וּמִמָּתְנָיו וּלְמַעְלָה כְּמַרְאֵה־זֹהַר כְּעֵין הַחַשְׁמַלָה׃

As I looked, there was a figure that had the appearance of fire: from what appeared as his loins down, [he was] fire; and from his loins up, his appearance was resplendent and had the color of amber. (8:2)

In all three of these verses the word hashmal is translated as "amber." This is based on the ancient Greek translation, the Septuagint, which used the Greek word elektron, meaning "amber." This tradition is in contrast to one found in the Talmud (Hagiga 13a-b), which says that chashmal is a kind of angel. In any case, since the visions are described as being "like" chashmal or having the color of chashmal, we can't conclusively say what it was from these verses, although it was likely something particularly radiant. The Akkadian cognate, elmesu, according to Tawil, refers to a "precious stone with the characteristic sparkle and brilliancy of fire."

Elektron (electrum in Latin) referred to an alloy of gold and silver. The same word was also used to refer to amber (the tree resin), because of the similar color. Rubbing amber gives an electrical charge, and so when the phenomenon of electricity was defined, the scientists turned to the Greek and Latin terms for amber to coin the word "electric."

The Hebrew poet Judah Leib Gordon followed the same logic around 1880, when he suggested to use chashmal to refer to electricity as well. 

Due to the rabbinic association of chashmal with angels, and the esoteric nature of Yechezkel's prophecy, there were many who opposed this secular use of chashmal.  (An alternate suggestion at the time was bazak -בזק "lightning.") But as we've discovered many times over the years, language has a power of its own, and chashmal is universally used in Hebrew today to refer to electricity.

And if you're curious, modern Hebrew has a different word to refer to "amber" - ענבר inbar. This word is borrowed from the Arabic anbar, as is the English word "amber." (However, as discussed here, it first entered Hebrew via European languages, and was spelled אמברא or אמבער, and only later began to be spelled ענבר to match the original Arabic.)  The etymology of anbar is unclear. Some say that the Arabic word comes from Persian, and others say that the similar Persian word comes from Arabic. Inbar is primarily heard today as a girl's name. It was in the top 50 girls names in the late 1980s and early 1990s, so as of this writing, you're most likely to find it used by women around 30 years old.