Vane

Part of speech: noun

Pronunciation: /veɪn/

Definitions

1. A flat blade or surface that rotates or pivots in response to wind or fluid movement, often used for direction indication or mechanical power
2. A device designed to catch the wind or fluid flow, which can also serve to indicate direction or contribute to the functioning of a machine
3. A flat or curved surface that moves with air currents to show wind direction or aid in mechanical applications

Etymology: The word started life as a piece of cloth. Old English "fana" meant a banner or flag, and it traces back to a Proto-Germanic root whose deepest sense was "something woven," so the earliest vanes were fabric streamers rather than metal arrows. Its relatives survive across the North Sea: Dutch "vaan" and German "Fahne" still mean a flag. The modern weathervane sense grew from the same idea. A flag fluttering on a pole shows which way the wind blows, and the shape of the flag was eventually replaced by a fixed, sharply cut sheet of metal, which turned freely on a spindle. In Middle English the word appeared in a variant spelling, a southern form of "fane," and the two survived side by side for centuries. "Fane" became obsolete, but it had already split off as a doublet, so the two words descend from one ancestor by different routes.

Synonyms: indicator, gauge, pointer, weathervane, blade