Definitions

1. noun

A line or surface of equal salinity on a map or diagram showing the distribution of salinity in the ocean or a lake.

“The isohalines on the map revealed the varying levels of saltwater in the nearby estuary.”

2. noun

A line or surface on a diagram or chart that marks the boundary between two areas of different salinity.

“The isohaline between the freshwater lake and the ocean marked a distinct change in the aquatic ecosystem.”