radius

Từ điển Oxford Advanced Learner 8th

ra·dius [radius radii] BrE [ˈreɪdiəs] NAmE [ˈreɪdiəs] noun (pl. radiiBrE [ˈreɪdiaɪ] ; NAmE [ˈreɪdiaɪ] )
1. a straight line between the centre of a circle and any point on its outer edge; the length of this line
compare ↑diameter
2. a round area that covers the distance mentioned from a central point
•They deliver to within a 5-mile radius of the store.
•Doctors wish to examine everyone living within a 10-mile radius of the factory.
3. (anatomy)the shorter bone of the two bones in the lower part of the arm between the elbow and the wrist, on the same side as the thumb
see also ↑ulna

Word Origin:
late 16th cent. (in sense 3): from Latin, literally staff, spoke, ray.

• Từ đồng nghĩa / Synonyms:
  spoke, wheel spoke, r