Straight lines from the centre to the surface of a sphere

• Sides of a pie slice, geometrically
• Shadows on an equatorial sundial, say
• Straight sides of a pizza slice, e.g
• Forelimb bones
• Pie cuts, essentially
• Spokes, say
• They go straight in a circle
• Pie chart dividers

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