Woodwind instrument
In an orchestra there may be two each of flutes, oboes, clarinets and bassoons.  In larger orchestras, particularly from the Romantic period onwards, there may be three or four.  Sometimes the extra instruments such as the piccolo are used.  If, for example, in an orchestral piece the third flute is marked “doubling piccolo”, it means that the person playing flute 3 will also play the piccolo.  However, if the piccolo plays at the same time as flute 3 they will obviously need an extra player for the piccolo part.