| Answer | Crossword Clue |
|---|---|
| AIRSAC | Hollow space in birds |
| cave | hollow space in the earth |
| caves | hollow space in the earth |
| LOOSELEGEND | The story of "Sleepy Hollow" set in outer space (or wherever else comes to mind)? |
| HOLE | Hollow space |
| CAVITY | Hollow space |
| RECESS | Hollow space. |
| DYSON | ... sphere (theoretical hollow space construct) |
| recesses | A hollow space inside something |
| hypocausts | A hollow space under the floor of an ancient Roman building, into which hot air was sent for heating a room or bath |
| hypocaust | A hollow space under the floor of an ancient Roman building, into which hot air was sent for heating a room or bath |
