What do we mean by traditional instrument ?

Is it:

a) An instrument on which a type of traditional music is played. or b) An instrument that has been around so long that a unique form of traditional music has developed on that instrument.

Most folk instruments start off in category a and if successful over a long period of time they may get into category b, however in different folk ideoms different rules may apply ie an instrument suited to Bulgarian music may not be suited to greek traditional music.

Some instruments like the fiddle are very chameleon like and can be successful in most music cultures achieving category b status quite easily.

Personally I think the guitar (especially in standard tuning) is not so versatile and for example in Irish music the bouzouki family of instruments though later arrivals, are overtaking it in becoming established.

Ian S