This is an agricultural and Biblical festival.
The word Sukkot is the plural of the Hebrew word sukkah, meaning booth or hut. During this holiday, Jews are instructed to build a temporary structure in which to eat their meals, entertain guests, relax, and even sleep. The sukkah is reminiscent of the type of huts in which the ancient Israelites dwelt during their 40 years of wandering in the desert after the Exodus from Egypt, and is intended to reflect God's benevolence in providing for all the Jews' needs in the desert.
In the Hebrew Scriptures, Sukkot is called:
“The Feast of Tabernacles (or Booths) ” (Lev. 23:34; Deut. 16:13-16; 31:10; Zech. 14:16-19; Ezra 3:4; 2 Chron. 8:13)
“The Feast of Ingathering” (Ex. 23:16, 34:22)
“The Feast” or “the festival” (1 Kings 8:2, 8:65; 12:32; 2 Chron. 5:3; 7:8)
“The Feast of the Lord” (Lev. 23:39; Judges 21:19)
“The festival of the seventh month” (Ezek. 45:25; Neh. 8:14)
“A holy convocation” or “a sacred occasion” (Num. 29:12)
In later Hebrew literature it is called “chag,” or "[the] festival."
Sukkot was agricultural in origin. This is evident from the name "The Feast of Ingathering," from the ceremonies accompanying it, and from the season and occasion of its celebration: "At the end of the year when you gather in your labors out of the field" (Ex. 23:16); "after you have gathered in from your threshing-floor and from your winepress" (Deut. 16:13). It was a thanksgiving for the fruit harvest (compare Judges 9:27). And in what may explain the festival’s name, Isaiah reports that grape harvesters kept booths in their vineyards (Isa. 1:8). Coming as it did at the completion of the harvest, Sukkot was regarded as a general thanksgiving for the bounty of nature in the year that had passed.
Since we share the same scripture in the Old Testament, Christians honor this too, calling it "The Feast of the Tabernacles," although it is marked and celebrated by only a handful of churches and forgotten by most.
Most Catholics know about this feast only because they recognize that there was a Jewish feast that Jesus attended in secret. I've blogged on that before but here is the cited scripture.
Paul also refers to his own celebration of the Feast of Tabernacles.
I think of it as "Jewish Thanksgiving" or "Biblical Thanksgiving." It actually makes much more sense to me than the American holiday of Thanksgiving, which occurs late in November, well after the harvest has (hopefully) taken place. So when it is Sukkot I tend to think of it as the "original Thanksgiving." The American Thanksgiving, nice as it is, is not Biblical, but is about the Protestants who had their lives saved by the generosity of American Indians who fed them during the dire winter weather. Sukkot preserves the agriculture harvest and the specifics of salvation history in connection with God himself and his Biblical directives.