Concertina and Free-reed instrument

Concertina noun - Free-reed instrument played like an accordion by pushing its ends together to force air through the reeds.

Free-reed instrument and concertina are semantically related. In some cases you can use "Free-reed instrument" instead a noun "Concertina".

Free-reed instrument noun - A wind instrument with a free reed.

Concertina and free-reed instrument are semantically related. Sometimes you can replace term "Concertina" with "Free-reed instrument", this terms are similar.