Related Clues:

• It's tough to crack
• Acorn, essentially
• Aficionado
• Bit of hardware
• Enthusiast plus,
• Squirrel's treat
• Trail mix bit
• Hazel, for one
• Bolt's partner
• Yo-yo
• Plumber's piece
• See 78-Across
• Squirrel snack
• Target at the fiesta
• Target of some batters