A 'beginner dulcimer'
General mountain dulcimer or music discussions
Generally "Beginner Dulcimer" means a less expensive instrument -- perhaps with a cardboard body, or a body made from birch veneer rather than 'planks' of walnut or maple or whatever. Also a less expensive set of tuning machines, perhaps friction tuners rather than geared tuners. Also, the action of a beginner may not be optimized for a particular style of playing.
The important factor is the precision of the fret layout, regardless of whether the body is made from Leggos, or cardboard or the finest lumber money can buy. If the layout of the frets is not precise, you simply will not get the proper notes, and that makes any instrument worthless.
No reason a "beginner" dulcimer can't be just part of your suite of instruments. I have one of Harpmaker Dave's Student Models which he slightly customized for me a number of years ago. It has a deeper sound than I prefer these days, but otherwise works as good or better than any of the other dulcimers I've owned or built.