I have been using the term "textus recepticus", to mean the original greek (NT) or hebrew (OT) documents. Wrongly as it turns out.

Is there a term for the original texts? One I can use correctly

If by originals, you mean the very manuscripts written on by the apostles, then the term is autographs.

If by originals you simply mean the original language texts which have been passed down to us, the term is apographs (these also are referred to as the originals by our confession).

Yes, autographs. In discussing inerrancy for example, it is often pointed out that only the autographs are truly inerrant.

If you want to sound really spiffy you can call them the autographa, and pronounce it aw-TAW-gra-fa.