A writing utensil for applying ink to a writing surface, and which could be a split reed (calamus), a frayed reed, a quill pen, etc.
A split reed, termed calamus in Latin (qalam in Arabic), was used to write on papyrus during antiquity; a frayed reed was used as a brush. These were replaced in the sixth century by the quill pen and animal-hair brushes, which were more flexible and thus better suited for work on parchment, a tougher material than papyrus. A quill is formed of the flight feather (one of the first five feathers) of the wing of a bird, often a goose - the word pen derives from the Latin for feather, penna. The feather was first hardened by heating or by soaking it in water and then immersing it in sand. Dutching is a form of curing in which a spatulate tool (dutching hook) is used to manipulate the cooling quill to produce a larger, flatter pen. Nibs were then cut with a knife, the angle of the cuts affecting the appearance of the script produced. Cursive (i.e., more rapidly written) scripts were generally produced with a thin pen and formal bookscripts with a broad pen. A nib cut at right angles to the shaft produces an informal, slanted-pen script in which the heads of letter strokes appear slanted, while a nib cut at an oblique angle to the shaft produces a formal, straight-pen script that has horizontal heads to the letter strokes.
Michelle Brown, Understanding Illuminated Manuscripts (Malibu, CA: J. Paul Getty Museum in association with the British Library, c1994).