An orchestra (/ˈɔːrkɪstrə/; Italian: [orˈkɛstra]) is a large instrumental ensemble typical of classical music, which combines instruments from different families, including bowed string instruments such as the violin, viola, cello, and double bass, brass instruments such as the horn, trumpet, trombone and tuba, woodwinds such as the flute, oboe, clarinet and bassoon, and percussion instruments such as the timpani, bass drum, triangle, snare drum, cymbals, and mallet percussion instruments each grouped in sections. Other instruments such as the piano and celesta may sometimes appear in a fifth keyboard section or may stand alone, as may the concert harp and, for performances of some modern compositions, electronic instruments.
A full-size Western orchestra may sometimes be called a symphony orchestra or philharmonic orchestra (phil-, Greek for “loving” + “harmonic”). The actual number of musicians employed in a given performance may vary from seventy to over one hundred musicians, depending on the work being played and the size of the venue. A chamber orchestra (sometimes concert orchestra) is a smaller-sized ensemble of about fifty musicians or fewer. Orchestras that specialize in the Baroque music of, for example, Johann Sebastian Bach and George Frideric Handel, or Classical repertoire, such as that of Haydn and Mozart, tend to be smaller than orchestras performing a Romantic music repertoire, such as the symphonies of Johannes Brahms. The typical orchestra grew in size throughout the 18th and 19th centuries, reaching a peak with the large orchestras (of as many as 120 players) called for in the works of Richard Wagner, and later, Gustav Mahler.