Possible Clues:

• Cartilage between bones that meet at a joint
• Knee cartilage
• Curved surface of liquid, caused by surface tension
• People discuss getting rid of cover for this on liquid
• Is about to break sets of dishes? Overfilled glass shows it!
• Crescent-shaped section of a lens
• One's affected by a sort of tension in the tube
• Curved upper surface of liquid in a tube
• Crescent
• Concavo-convex lens