Debra Knodel Hi there.
Folk harp is a very misleading term, largely becayse of the invalidity of the term folk music.
Harp appears in manuscripts in the 17th C. to distinguish it from the clarseach. The most widely held view is that the clarseach is wire strung whilst the harp is gut. My personal theory is that, as the 2 names roughly coincide with the chromaticisation of the harp, Clarseach refers to a diatonic instrument and harp a chromatic instrument. Neither of these were folk instruments as they were in use for the performance of the 'classical' music of the time. Egan, the first maker to produce a small 'celtic' called it a portable and modeled his first designs after the historic harps.