Related Clues:

• Lead-in to sine, cosine, or tangent
• Zero, for one
• D.C. office shape
• Racetrack shape, probably
• Part of the Toyota logo
• Sesame-seed shape
• Basic track shape
• Palette shape
• Common mirror shape
• Flattened-out circle
• Shot-put path
• Zero, essentially
• A pop-up has one
• Parabola, for one
• A jump shot forms one