When I was a young child, we used to refer to the Kohanim engaged in Birkat Kohanim as going up “to duchan” or “duchening.” Because of that usage, I always thought that duchan was a verb in Yiddish that referred to the act of “blessing” other people. But as Rabbi Eliyahu HaBachur already points out in Sefer Tishbi, the word duchan is actually a noun that refers to the “platform” upon which the Kohanim stood when reciting the Priestly Blessings. In this essay, we look at a whole slew of words in Hebrew — both Biblical Hebrew and Rabbinic Hebrew — that are used in reference to “platforms.” These words include kan, duchan, bimah, basis and itztaba.
Before we discuss the word duchan, I’d like to begin with the word kan (sometimes vocalized as kein), which refers to the “base,” “foundation,” “platform,” “stand,” or “pedestal” upon which something stands. For example, this term is used in the Bible when referring to the base of the kiyor (“water basin”) in the Tabernacle. It can also be used in a more abstract sense to refer to a person’s professional post (meaning, his job — on which his livelihood stands), as when Joseph foretold that the Pharoah will reinstate his jailed butler, Joseph said: “He will return you on your kan [stand/post/position]” (Gen. 40:13), which is precisely what happened (Gen. 41:13).
Now we can start talking about the word duchan. That word does not appear at all in the Bible, but makes it first appearances in Mishnaic Hebrew, occurring thrice in the Mishnah. In the Babylonian Talmud, the term duchan also assumed an additional meaning in reference to the place upon which Kohanim stood when blessing the Jewish People (even outside of the Temple). For example, Rabbi Yose said about himself that he never went against what his colleagues told him, adding that even if they would tell him to go up to the duchan to recite the Priestly Blessings, he would do so, despite knowing that he is not a Kohen (Shabbat 118b). Other examples of the word duchan appearing when discussing the Priestly Blessings include: the warning that a Kohen should not add his own personal blessings to the recitation of the Priestly Blessings (Rosh HaShanah 28b), the rule that a Kohen may not ascend the duchan while wearing shoes (Rosh HaShanah 31b, Sotah 40a), the assertion that a Kohen who fails to ascend the duchan to bless the people has violated three positive commandments (Sotah 38b, Menachot 44a), and the story of a young Rabbi Tarfon ascending the duchan with his uncle and hearing the Kohen Gadol recite Hashem's ineffable name in the Temple (Kiddushin 71a). It is pretty clear that the Yiddish verb duchenen derives from the noun duchan in the sense of the post from which Kohanim blessed the people.
What is the etymological basis for the word duchan? Rabbi Tzvi Hirsch Ferber (Kerem Tzvi to Num. 6:23) offers another two ways of understanding the etymology of duchan. Firstly, he suggests parsing duchan as a portmanteau of the Greek prefix du- (“double”) and the Biblical Hebrew kan ("base"). In doing so, he explains that the term duchan refers to the reality that an elevated platform might be double as wide as the stairs at its base that lead it up to it, hence it literally means “double base.”
Alternatively, he explains the word duchan as related to the Biblical Hebrew root DALET-(VAV)-KAF, which refers to the verb of "smashing/flattening." This makes sense because the duchan platform would typically be a small area, which means that those standing there might have to squish together for there to be enough room for everyone.
Following this second explanation, we can compare the sense development of the root DALET-(VAV)-KAF to similar developments in the derivatives of the Proto-Indo-European root plat- that originally referred to the act of “spreading/flattening.” That root eventually yielded nouns that refer to a flat surface, like the English words flat (via the interchangeability of f and p), place (which derives from the Greek work platus), platy, plaza, plate, plateau, and more. The same PIE root is also the etymon of the Rabbinic Hebrew term platya (“street/highway”), as well as the Modern Hebrew word plata (“flat surface for heating foods”). All of these words refer to flat surfaces or platforms of sorts, and are derived from the root that refers to the act of making something flat. The same could be true in Hebrew, whereby the word for duchan — which is a flat surface — might be derived from the verb used in reference to “flattening” things. A similar point is made by Rabbi Ernest Klein.
