A longitudinalstrip projecting from an object to strengthen it, or to enter a channel in another object and thereby prevent displacement sideways but permit motion lengthwise; a spline.
Kind; nature; species (from the proverbial phrase "birds of a feather").
One of the two shims of the three-piece stone-splitting tool known as plug and feather or plug and feathers; the feathers are placed in a borehole and then a wedge is driven between them, causing the stone to split.