| Answer | Crossword Clue |
|---|---|
| altitude | the height of a thing above a reference point, as sea level |
| hypsometers | A device for calibrating thermometers at the boiling point of water at a known height above sea level or for estimating height above sea level by finding the temperature at which water boils |
| hypsometer | A device for calibrating thermometers at the boiling point of water at a known height above sea level or for estimating height above sea level by finding the temperature at which water boils |
| highest | Far above ground, sea level, or another point of reference |
| subsonic | noting or pertaining to a speed less than that of sound in air at the same height above sea level |
| altitudes | The height of an object or point in relation to sea level or ground level |
