Euclid's arms?

• R's, in geometry
• Spoke more than once?
• Spoke multiple times?
• Direct lines to centre one added to incomplete set?
• Diameter fractions
• Broadcaster cut international lines
• Semidiameters
• Diameters halved
• Straight sides of a pizza slice, e.g

Wiktionary Word definitions in Wiktionary
n. (plural of radius English)