What is "Bikurei K'tzir Chitim" referring to? Why are they called by that name?
Rashi #1: It refers to the Sh'tei ha'Lechem on Shavu'os, so-called because they comprise the first Minchah that is brought from that year's wheat harvest. 1
Rashi #2 (in Rosh Hashanah, 16a): It refers to the Bikurim, which may only be brought from Shavu'os and onwards.
Rashi: Bearing in mind that the Omer on Pesach is from barley.
Why does the Torah call Succos "Chag ha'Asif"?
Rashi: Because it corresponds to the ingathering of the crops - from the field into the house.
What is the meaning of "Tekufas ha'Shanah"?
Rashi: It means when the new year comes around (at the beginning of the year).
What is the significance of the term "Tekufas ha'Shanah"?
Sanhedrin, 13a: It refers to the winter solstice, and it teaches us that the whole of Sukos must take place in the winter solstice - Consequently, if the winter solstice falls even one day after the fifteenth of Tishri, the Sanhedrin will declare a leap-year. 1
This is the opinion of R. Yehudah. See Torah Temimah, note 33, who explains the isuue in detail.
