feather

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun One of the light, flat growths forming the plumage of birds, consisting of numerous slender, closely arranged parallel barbs forming a vane on either side of a horny, tapering, partly hollow shaft.
• noun A feathery tuft or fringe of hair, as on the legs or tail of some dogs.
• noun Character, kind, or nature.
• noun A strip, wedge, or flange used as a strengthening part.
• noun A wedge or key that fits into a groove to make a joint.
• noun The vane of an arrow.
• noun A feather-shaped flaw, as in a precious stone.
• noun The wake made by a submarine's periscope.
• noun The act of feathering the blade of an oar in rowing.
• intransitive verb To cover, dress, or decorate with feathers or featherlike projections.
• intransitive verb To fit (an arrow) with a feather.
• intransitive verb To thin, reduce, or fringe the edge of (wood, for example) by cutting, shaving, or making thinner.
• intransitive verb To spread (paint, for example) thinly at the edges so as to blend with the surrounding area.
• intransitive verb To shorten and taper (hair) by cutting and thinning.
• intransitive verb To blur or soften the edge of (an image).
• intransitive verb To apply (a brake, throttle, or other control) gently or slightly and steadily.
• intransitive verb To turn (an oar blade) almost horizontal as it is carried back after each stroke.
• intransitive verb To alter the pitch of (a propeller) so that the chords of the blades are parallel with the line of flight.
• intransitive verb To alter the pitch of (the rotor of a helicopter) while in forward flight.
• intransitive verb To turn off (an aircraft engine) while in flight.
• intransitive verb To grow feathers or become feathered.
• intransitive verb To move, spread, or grow in a manner suggestive of feathers.
• intransitive verb To become thin or less dense at the edges.
• intransitive verb To feather an oar.
• intransitive verb To feather a propeller.
• idiom (feather in (one's) cap) An act or deed to one's credit; a distinctive achievement.
• idiom (feather (one's) nest) To grow wealthy by taking advantage of one's position or by making use of property or funds left in one's trust.
• idiom (fine/good) /high) In excellent form, health, or humor.

from The Century Dictionary.

• To drop (melted metallic tin) into cold water, which has the effect of spreading it out with a feathery appearance.
• To make a quivering movement of the tail: said of dogs.
• noun One of the epidermal appendages which together constitute the plumage, the peculiar covering of birds; also, collectively, the plumage.
• noun Something in the form of a feather, or resembling nearly or remotely the standard of a feather; something made of feathers.
• noun Specifically — A plume.
• noun In founding, a thin rib cast on iron framing to strengthen it and resist bending or fracture.
• noun A slip inserted longitudinally into a shaft or arbor, and projecting so as to fit a groove in the eye of a wheel.
• noun One of two pieces of metal placed in a hole in a stone which is to be split, a wedge-shaped key or plug being driven between them for this purpose.
• noun In joinery, a projection on the edge of a board which fits into a channel on the edge of another board, in the operation of joining boards by grooving and feathering, or grooving and tonguing, as it is more commonly called.
• noun On a horse, a sort of natural frizzling of the hair, which in some places rises above the smooth coat, and makes a figure resembling the tip of an ear of wheat.
• noun A foamy spray of water thrown up and backward on each side of the cutwater of a swiftly moving vessel, or from the edge of an oar when turned horizontally. See feather-spray.
• noun The fringe of hair on the back of the legs, on the neck, or on the ears of some breeds of dogs, as setters. Also feathering
• noun In precious stones, an irregular flaw. See the extract.
• noun The feathered end or string-end of an arrow.
• noun Kind; nature; species: from the proverbial phrase “birds of a feather”—that is, of the same species.
• noun In sporting, birds collectively; fowls: as, fur, fin, and feather.
• noun Among confectioners, one of the degrees in boiling sugar, preceded by the blow, and followed by the ball.
• noun Something as light as a feather; hence, something very unimportant; a trifle.
• noun In rowing, the act of feathering. See feather, v. t., 6.