The noun SALINITY has 2 senses: 1. the taste experience when common salt is taken into the mouth. 2. the relative proportion of salt in a solution. Familiarity information: SALINITY used as a noun is rare.he noun SALINITY has 2 senses: 1. the taste experience when common salt is taken into the mouth. 2. the relative proportion of salt in a solution. Familiarity information: SALINITY used as a noun is rare.