folk instrument; traditional instrument
Refers to musical instruments rooted in a particular culture or ethnic group, often used in traditional music.
Folk instruments from around the world are exhibited in this museum.
He went to Africa to learn how to play traditional instruments.
和楽器 specifically refers to traditional Japanese instruments, while 民族楽器 is a broader term covering folk instruments from any culture.
Compound of 民族 (minzoku, 'ethnic group, folk') and 楽器 (gakki, 'musical instrument').