turbidity of water

https://doi.org/10.1351/goldbook.15117
Extent to which the clarity of water is reduced by the presence of suspended or other matter that causes light to be scattered and absorbed rather than transmitted (in straight lines) through the sample.
Source:
PAC, 2009, 81, 829. (Glossary of terms used in ecotoxicology (IUPAC Recommendations 2009)) on page 960 [Terms] [Paper]