This sense is not to be confused with the prehistoric stone tools.
The term burin refers to a tool used by engravers that has a thin, pointed blade and is used to etch or cut. The first known use of the word dates back to France in the mid-1600s, when the term was coined for the tool we know today.
The burin consists of a rounded handle shaped like a mushroom, and a tempered steel shaft coming from the handle at an angle and ending in a very sharp cutting face.
The most ubiquitous types have a square or lozenge face; a high-end repertoire has many others. A tint burin has a square face with teeth, to create many fine, closely spaced lines. A stipple tool allows for the creation of fine dots. A flat burin has a rectangular face, and is used for cutting away large portions of material at a time.
An engraving burin is used predominantly by intaglio engravers, but also by relief printmakers in making wood engravings. Usually an engraver will have several tools, of different sizes and shapes of cutting face.
The burin is held at approximately 30° to the surface. The index and middle fingers guide the shaft, while the handle is cradled in the palm. The 16th-century Dutch engraver Hendrik Goltzius found his unusually malformed hand was well suited for cradling and guiding a burin.
In its earliest uses the burin cut and carved materials to create sketches, or cut meat or thinner materials. Some art from the Lower Paleolithic time period, such as sketches and pictures, can be attributed to the use of the burin as an etching or engraving tool.
Media related to Engraving burins at Wikimedia Commons