1590s, "cross-shaft," from Latin radius "staff, stake, rod; spoke of a wheel; ray of light, beam of light; radius of a circle," of unknown origin. Perhaps related to radix "root," but Tucker suggests connection to Sanskrit vardhate "rises, makes grow," via root *neredh- "rise, out, extend forth;" or else Greek ardis "sharp point."
The geometric sense first recorded 1610s. Plural is radii. Meaning "circular area of defined distance around some place" is attested from 1953. Meaning "shorter bone of the forearm" is from 1610s in English (the Latin word had been used thus by the Romans).
实用例句
1. Nigel has searched for work in a ten-mile radius around his home.
奈杰尔一直在他家周围10英里的范围内找工作。
来自柯林斯例句
2. They deliver to within a 5-mile radius of the store.
他们在距离商场5英里的范围内送货上门。
来自《权威词典》
3. He has visited every shop within a radius of two miles.
周围两英里以内的店铺他都去过.
来自《简明英汉词典》
4. We are measuring the radius of the circle.
我们正在测量圆的半径.
来自《简明英汉词典》
5. A special load balancing server designed for solving this problem can manage multi RADIUS servers.