Emily Dickinson Lexicon

FEATH'ER, or FETH'ER, n. [Sax. fether; G. feder; D. veder; Dan. fiær; Sw. fieder; allied probably to πτερον, and πεταλον, from πεταω, to open or expand.]

1. A plume; a general name of the covering of fowls. The smaller feathers are used for the filling of beds; the larger ones, called quills, are used for ornaments of the head, for writing pens, &c. The feather consists of a shaft or stem, corneous, round, strong and hollow at the lower part, and at the upper part, filled with pith. On each side of the shaft are the vanes, broad on one side and narrow on the other, consisting of thin lamins. The feathers which cover the body are called the plumage; the feathers of the wings are adapted to flight.
2. Kind; nature; species; from the proverbial phrase, “Birds of a feather,” that is, of the same species. [Unusual.] I am not of that feather to shake off / My friend, when he most needs me. Shak.
3. An ornament; an empty title.
4. On a horse, a sort of natural frizzling of the hair, which, in some places, rises above the lying hair, and there makes a figure resembling the tip of an ear of wheat. Far. Dict. A feather in the cap, is an honor, or mark of distinction. [Fether is the better spelling.]