Related Clues:

• Keep from escaping
• Symbol on a Cowboy's helmet
• Ring bearer?
• Apple or pear
• Polaris, e.g.
• Ratings unit
• Kind of witness
• Forest growth
• General acquisition
• See 51-Down
• See 48-Across
• It may require surgery
• Swing site
• It has a bark but no bite
• Award for a good student