| Answer | Crossword Clue |
|---|---|
| troughs | long depression, as between two waves |
| trough | long depression, as between two waves |
| quadrature | A phase difference of 90░ between two waves of the same frequency, as in the color difference signals of a television screen |
| valley | long depression between uplands or mountains |
| col | a depression between two mountains |
| cols | COL, a depression between two mountains |
