Related Clues:

• Opening in a sweater?
• One place for a ring
• Streak, as in marble
• Brain section
• Miner's find
• Hoop setting
• Breathing space
• Study intently (with "over")
• Blood conduit
• Thin blue line, say
• Lung division
• Ore deposit
• Ring location?
• It goes to the heart
• Shrimp discard