the orchestra has how many primary instrument groups
Orchestra The typical symphony orchestra consists of four groups of related musical instruments called the woodwinds, brass, percussion, and strings (violin, viola, cello and double bass). Other instruments such as the piano and celesta may sometimes be grouped into a fifth section such as a keyboard section or may stand alone, as may the concert harp and electric and electronic instruments. The orchestra, depending on the size, contains almost all of the standard instruments in each group.
Concerto A concerto (/kənˈtʃɛərtoʊ/; plural concertos, anglicised from the Italian concerti, which is also used in English) is a musical composition, whose characteristics have changed over time. In the 17th century, "sacred works for voices and orchestra were typically called concertos."[1] J. S. Bach "...was thus reflecting a long-standing tradition when he used the title 'concerto' for many of the works that we know as cantatas."[1] However, in recent centuries and up to the present, a concerto is a piece usually composed in three parts or movements, in which—usually—one solo instrument (for instance, a piano, violin, cello or flute) is accompanied by an orchestra or concert band.