Definition
An instrument that measures the speed of moving air. The most common type uses a set of cups mounted on a vertical shaft; the wind pushes the cups around, and the rotation rate is converted into a wind speed reading.
Plain English
A device that measures how fast the wind is blowing.
Context Anchor
Seen in airport weather equipment, weather reports, and discussions of wind conditions before takeoff or landing.
Derivation
From the Greek anemos meaning 'wind' and metron meaning 'measure'. Literally, a 'wind measurer'. The Greek root anemos appears in other weather-related words and helps lock in that this instrument is specifically about wind, not air pressure or temperature.
Why Pilots Care
Accurate wind speed data helps determine safe takeoff and landing performance and crosswind limits.
Intuition Check
An anemometer measures wind speed, not wind direction. Wind direction is shown by other equipment, such as a wind vane or windsock.
Example Sentence 1
The anemometer at the field showed a steady 15 knots, well within the aircraft's crosswind limit.
Example Sentence 2
During the weather briefing the anemometer readings showed gusts exceeding the aircraft's crosswind limit.