| Answer | Crossword Clue |
|---|---|
| RADIUS | Half the diameter |
| RADII | They're half the diameter |
| RADIUS | Half a diameter |
| REAM | Expand the diameter |
| RADII | Two make the diameter |
| VASOMOTOR | Regulating the diameter of blood vessels |
| CALIBER | Diameter of the bore of a gun |
| CALIBRATE | Ascertain the diameter of, as a gun bore. |
| FERMI | Unit of length that's roughly the diameter of a proton |
