A stylus (plural: styli or styluses) is a writing utensil. The word is also used for a computer accessory (PDAs). It usually refers to a narrow elongated staff, similar to a modern ballpoint pen. Many styluses are heavily curved to be held more easily.
Styli were first used by the ancient Mesopotamians in order to write in cuneiform, Egyptians (Middle Kingdom), and the Minoans of Crete (Linear A and Cretan Hieroglyphic) made in various materials: reeds that grew on the sides of the Tigris and Euphrates rivers and in marshes and down to Egypt where the Egyptians used styluses from sliced reeds with sharp points; bone and metal styli were also used. Cuneiform was entirely based on the "wedge-shaped" mark that the end of a cut reed made when pushed into a clay tablet, hence the name "cuneiform" from Latin cuneus = "wedge". The linear writings of Crete in the first half of the second millennium BC were made on sun dried clay tablets that were left to dry in order to become 'leather' hard before they were incised by the stylus. The linear nature of the writing was also dictated by the use of the stylus.
"An iron instrument (Ov. Met. IX.521; Martial, XIV.21), resembling a pencil in size and shape, used for writing upon waxed tablets (Plaut. Bacch. IV.4.63; Plin. H.N. XXXIV.14). At one end it was sharpened to a point for scratching the characters upon the wax (Quintil. i.1 §27), while the other end being flat and circular served to render the surface of the tablets smooth again, and so to obliterate what had been written. Thus, vertere stilum means to erase, and hence to correct, as in the well-known precept saepe stilum vertas (Hor. Sat. 1.10.72; Cic. Verr. II.41)."
Styli are used to make dots as found in folk art and Mexican potterty artifacts. Oaxaca dot art is created using Styli.
Several technologies were used to record the sounds, beginning with wax cylinders. The harder the material used, the harder the stylus has to be. The styli for playing vinyl records are made out of Sapphire or diamond.
A stylus may also be used to scribe a recording into smoked foil or glass. In various instruments this method may be used instead of a pen for recording as it has the advantage of being able to operate over a wide temperature range, does not clog or dry prematurely, and has very small friction in comparison to other methods. These characteristics were useful in certain types of early seismographs and in recording barographs used in determining sailplane altitude records.