Jamboree \JAM-buh-ree\ , noun;
1. A carousal; any noisy merrymaking
2. A large gathering, as of a political party or the teams of a sporting league, often including a program of speeches and entertainment
3. A large gathering of members of the Boy Scouts or Girl Scouts, usually nationwide or international in scope
This word dates to the 1868 in American English. It's origins are unknown, but there are a couple of theories:
It may be a blend of jam or jabber and shivaree. Shivaree is first attested in 1834 as an alteration of charivari from French charivari, which derives from Old French chalivali ("discordant noise made by pots and pans"). The French words come from Late Latin caribaria ("a severe headache") which was a borrowing from Greek karebaria ("headache").
Jamboree may also come from French bouree, which is a kind of rustic dance.
Another theory is that it is of Hindu origin.
In 1920 the International Rally of Boy Scouts was named Jamboree, and the word has stuck within that organization ever since.
Today's word and the first definition were both taken from Dictionary.com's 'Word of the Day' for Wednesday, April 27
Etymologies come from the Oxford English Dictionary and/or Etymonline.com