Related Clues:

• Empty or vacant, like space
• Hole as in tooth
• A break in something continuous, like a hedge
• A hollow within a solid, say tooth
• Absence of matter
• Breach or lacuna
• Area empty of matter
• A small parting, in hedge or teeth
• Emptiness, empty space
• Open space between two things, mind it
• Space entirely devoid of matter
• Null or emptiness
• After 50 I had something empty
• The doctor around a space that's open
• There's nothing in it