A short, double-edged, (usually) non-folding blade on the end of a long tang in a wood or ivory handle, used to “erase” ink by scraping it from parchment, vellum, and paper. Often sold as “Civil War scalpels.” The style that is like a short dagger is, without its handle, sometimes sold to the unsuspecting as a “trade arrowhead”. Caveat emptor.
The most common style of ink eraser blade.