n. 1 (in full weather-vane) a revolving pointer mounted on a church spire or other high place to show the direction of the wind (cf. WEATHERCOCK). 2 a blade of a screw propeller or a windmill etc. 3 the sight of surveying instruments, a quadrant, etc. 4 the flat part of a bird's feather formed by the barbs. vaned adj. vaneless adj.
[ ME, southern & western var. of obs. fane f. OE fana banner f. Gmc ]