A vane is a device or object designed to show or measure the direction of the wind by rotating on an axis. It is often mounted on an elevated structure, such as a roof or spire, where the wind moves the vane to point in the direction from which the wind is coming. Vanes can also refer to flat blades or thin objects that rotate or redirect fluid flow, such as in windmills or fans. Additionally, in ornithology, a vane is the flattened surface of a feather formed by barbs. Commonly, vanes are included in weather instruments known as wind vanes or weather vanes, which help indicate wind direction for meteorological purposes. They are sometimes decorative and often have a pointer or shape (like a rooster) that rotates with the wind. Vanes are critical in applications like weather monitoring, sailing, aviation, and construction for assessing wind conditions.
