noun

1. Zool. any of the growths covering the body of a bird or making up a large part of the wing surface, as down or contour feathers: a typical contour feather consists of a horny central shaft, partly hollow, from which light, soft, narrow barbs, with interlocking barbules and barbicels, extend to form a thin, flat surface
2. a feather or featherlike part fastened to the shaft of an arrow to help control its flight
3. anything like or suggesting a feather or feathers in appearance, lightness, etc., as
   1. a trifle
   2. a projecting part, esp. for fitting into a groove
   3. an irregular flaw in a gem
   4. the fringe of hair along the tail and along the back of the legs of some dogs
4. Archaic
   1. plumage
   2. attire; dress
5. class; kind enthusiasts of every feather
6. frame of mind; temper; vein
7. the act of feathering an oar or propeller

Etymology: ME fether < OE; akin to Ger feder < IE base *pet-, to fall, fly > Gr pteron, wing, piptein, L petere, to fall, Sans pátati, (he) flies

transitive verb

1. to provide (an arrow, etc.) with a feather
2. to cover, fit, or fringe with or as with feathers
3. to give a featheredge to
4. to join by inserting a wedge-shaped part into a groove
5. to turn (the blade of an oar) parallel to the line of movement in recovering after a stroke, so as to offer the least resistance to air or water
6. 1. to turn (the blade of a propeller) on its shaft so that its leading and trailing edges are nearly parallel with the airplane's line of flight, thus preventing engine damage caused by airflow turning the propeller during an engine failure
   2. to change the angle of the blades of a helicopter rotor

intransitive verb

1. to grow, or become covered with, feathers
2. to move, grow, or extend like feathers
3. to look like feathers
4. to feather an oar or propeller