Salinity n. : Salineness.

Example:
What is the Salinity of a hydrothermal vent?

Taxonomy
salinity, salts, ocean, waters, Salinity Scale, salt content, Seawater, free encyclopedia, body of water, saline water, ratio, organisms, Unesco, Pap, Mar. Sci, sea surface salinity, Water salinity, water bodies.

Defination from the web:
salinity not as percent, but as parts per thousand (ppt or ‰), which is approximately grams of salt per liter of solution. ... Prior to 1978, salinity or halinity was expressed as ‰ usually based on the electrical conductivity ratio ...