An opaque disc, typically white, used to gauge the transparency of water by measuring the depth—known as the Secchi depth—at which the disc ceases to be visible from the surface.
More example sentences
- Overall difference between species in use of Secchi depths varied by habitat type.
- Mean Secchi depths tended to be higher in 1996 than in 1997, but these differences also were not statistically significant.
- Temperature (in degrees Celsius) was measured at the surface and close to the bottom, and the Secchi depth was determined.
early 20th century: named after Angelo Secchi (1818–78), Italian astronomer.
Definition of Secchi disc in:
- The US English dictionary