noun
sextant
SEK-stunt/ˈsekstənt/
An instrument used in navigation to measure the angle between visible objects.
The marine sextant measures angles between the sun and the sea horizon.
Etymology
The name “a sixth part” refers to the instrument’s graduated arc, which spans one-sixth of a circle. That arc is used to measure angles for navigation.
In context
a Sextant a handheld instrument used to measure angles between the Sun and Moon and Horizon as a backup to their GPS systems
More examples
- She adjusts the sextant until the star appears level with the horizon.
- A sextant and an accurate clock help sailors determine their position.
- The navigation class practices taking measurements with sextants.
Forms
sextant · sextants
Similar words
- octant
- Uses an eighth-circle arc rather than a sixth-circle arc.
- quadrant
- Uses a quarter-circle scale, often for measuring celestial altitude.