| Answer | Crossword Clue |
|---|---|
| FERMI | Unit of length used for measuring nuclear distances |
| angstroms | A unit of length equal to one hundred-millionth of a centimeter, 10?10 meter, used mainly to express wavelengths and interatomic distances |
| mil | unit of length equal to 1/1000 inch used especially in measuring thickness (as of plastic films) |
| sextants | an instrument for measuring angular distances used especially in navigation to observe altitudes of celestial bodies (as in ascertaining latitude and longitude) |
