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Why do we call it masechet Beitza now, and not masechet Yom Tov, as was apparently once common? Unlike the parshiot, which are named after their first words, masechtot are all named after topics, except Beitza. This is particularly odd considering that today, many people actually call it "Bei'a" to avoid a word not appropriate for mixed company. So why not just call it "Yom Tov"?

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Who's "we"? Who calls it "Beitza"? Don't you call it "Aharei" and not "Aharei Mos"? ;-) – Yahu Apr 26 '10 at 20:40
I call it "Beitzah" (and similarly for the item on the Seder plate). I don't think the word has the same (improper) resonance it used to - maybe in the plural, but not in the singular. – Alex Apr 27 '10 at 2:31
Alex, I was just being facetious and comparing calling Beitzah by the ancient name Yom Tov to calling Aharei Mos by the old and shorter version "Aharei" – Yahu Apr 27 '10 at 20:24
I know, I was responding more to Jeremy's original question. – Alex Apr 28 '10 at 16:45
up vote 9 down vote accepted

See the beginning of Rabbenu Chananel on Masseches Beitzah, where he - or whomever copied the manuscript the printed text is based on - began it with the following rhyming ditty:

אתחיל מסכת ביצה בעזרת גדול העיצה

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Maybe because "Yom Tov" just sounds like too generic a name? There are, after all, several other masechtos that discuss, and/or are named for, specific Yamim Tovim.

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what about masechet Taharot? that could be anything! I was thinking there must be some historical reason for the shift, since many Rishonim definitely called it Y"T. – Jeremy Apr 28 '10 at 16:10
True, but then (quite aside from the fact that fewer people are familiar with Seder Taharos than with Seder Moed), none of the masechtos of Taharos are named for specific pure items; they're named either for things that can be tamei or tahor (Kelim, Yadayim, etc.) or for things that are indeed tamei (Negaim, Zavim, etc.). Whereas in Moed, for example, you've got Rosh Hashanah, which is named for a specific Yom Tov. – Alex Apr 28 '10 at 16:48

One of the reasons we call the Mesechta Beiya and not Beitza is in order to avoid any errors. The Gemara in Sanhedrin, daf 5, tells of an occasion when Rebbe came to a city and the people were kneading their doughs in water that was tamei. They explained that a learned man had once taught them that 'water of Betzayim does not allow it to become tamei'.

After investigating, it turned out that this talmid chacham has said 'water of Beitzim' - meaning water of eggs — not Betzayim (pond water), and the people of the town took it to mean water from the pond.

To avoid further confusion---and resulting halchic transgression---between the two similar words, people began pronouncing it 'Beiya'.

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I don't see how this answers the question at all. – Ypnypn Nov 2 '15 at 23:10

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