means A quill is a writing implement made from the stiff, hollow shaft of a large bird's feather, its tip cut and split to hold and release ink.

from From Middle English 'quil,' meaning a reed or hollow stalk, likely borrowed from a Low German or Middle Low German source like 'quiele.' The root sense is that hollowness — the empty tube that could carry ink, and the same idea that lets 'quill' also name a porcupine's spine or a weaver's bobbin. The writing tool took flight when scribes discovered that a goose or swan feather, hardened and slit at the point, made a finer pen than the old reed — and so for over a thousand years, the fate of the word and the feather were one.