Short answers, pulled from the story.
An orchestra is a large instrumental ensemble typical of classical music or jazz that combines instruments from different families. It typically has four main sections: strings, woodwinds, brass, and percussion, sometimes with a fifth keyboard section and a harp.
The term orchestra derives from the Greek orchestra, the name for the area in front of a stage in ancient Greek theatre reserved for the Greek chorus. A full-size Western orchestra may be called a philharmonic orchestra, from the Greek phil, meaning loving, and harmony.
Beethoven is generally credited with consolidating the standard complement of doubled winds and brass after Haydn and Mozart, almost always including paired flutes, oboes, clarinets, bassoons, horns, and trumpets. His Symphony No. 9 calls for a second pair of horns, and four horns has since become standard.
The Vienna Philharmonic did not accept women to permanent membership until 1997, when members agreed on the 28th of February 1997 to admit the harpist Anna Lelkes. In 2008, violinist Albena Danailova became one of the orchestra's concertmasters, the first woman to hold that position there.
In 1922, the Soviet orchestra Persimfans formed without a conductor because its founders believed the ensemble should model the ideal Marxist state in which all people are equal. It used a committee for tempos and survived ten years before Stalin's cultural politics disbanded it by removing its funding.
A symphony or philharmonic orchestra usually has over eighty musicians, in some cases over a hundred. The typical orchestra grew through the 18th and 19th centuries, reaching as many as 120 players in the works of Richard Wagner and later Gustav Mahler.