What's the exact difference between a dulcimore and dulcimer
Instruments- discuss specific features, luthiers, instrument problems & questions
The Appalachian dulcimer is a folk instrument that evolved in the US from various folk instruments familiar to immigrants, such as hummel, langelik, langspil, scheitholt, epinette, etc. The earliest currently known dated Appalachian dulcimer has a date from I believe the 1830s, but doubtless they were being made in the US somewhat earlier. There are some good dulcimer history books out there that should be read by anyone interested in the background of dulcimers, as currently known.
The fact is we will likely never know exactly when/where/bywhom the American lap dulcimer was precisely 'invented'. Such records were never officially kept by anyone, and folk instruments can be fragile or be stored in barns- many have not survived as long as instruments like violins or pianos that were considered more valuable and thus were better cared for over time. Compared to more widespread commercial instruments, the surviving documentation on mtn dulcimers is sparse.
As to names, like Dusty said there are regional variations in spelling and pronunciation, especially when it comes to informal folk culture. The 'dulcimer' in St James Bible likely refers to ancient instruments that were more like psalteries or hammered dulcimers, or perhaps even bagpipe-like.
There is no Official Rule Book that governs how mountain dulcimers should be called, played, or tuned. Instead, there are musicians, scholars, online fans, and builders who all have their own preferences and ideas on classification, tradition, and features of the instrument. The mtn dulcimer is definitely classified in the broad zither family as opposed to the necked 'lute' family, but beyond that people get into classification and feature preferences that can be relative according to their own ideas.
If I started posting regularly about distinct characteristics of the "Dulcimonium"... then after a few years everyone might well consider that to be a verified and distinct variety of mountain dulcimer, not to be confused with Dulcimores or Galax dulcimers or box dulcimers or modern dulcimers. I could go on about how this or that feature makes something a Dulcimonium or not a Dulcimonium... a dulcimonium must have gut strings, six of them, and have a long triangular body shape and must have wooden frets and zither tuning pins... or else it's not a true dulcimonium.
What I mean is that there is no actual official 'Bible' or rulebook of mountain dulcimers. With enough repetition and enthusiasm, anyone could make Dulcimoniums 'happen'.
BTW please excuse my evening ramblings, ..and know that i certainly don't intend to offend anyone!