| Answer | Crossword Clue |
|---|---|
| femtosecond | one quadrillionth part of a second |
| Answer | Crossword Clue |
|---|---|
| femtosecond | one quadrillionth part of a second |
Crossword
a puzzle consisting of a grid of squares and blanks into which words crossing vertically and horizontally are written according to clues.