Possible Clues:

• Rim
• Projecting edge
• Projecting collar or rim for keeping a position on a rail
• Raised edge of baked product, turnover for example
• Projecting rim of a metal beam
• Flat rim on a wheel to keep it on a rail
• Edge of tart topping, say, lifted
• I-beam feature
• Lip having large teeth almost covering length
• Boot-to-ski connector