The term 'long-necked instrument' can refer to two different instruments: the SITAR (5 letters) and the LUTE (4 letters). The SITAR is a stringed instrument originating from India, and is used in Hindustani classical music. It has a long neck and a gourd-shaped body. The LUTE is a plucked string instrument with a long neck and a pear-shaped body. It is used in many genres of music, including classical, folk, and popular music.