seawater

American  

[see-waw-ter, -wot-er] / ˈsiˌwɔ tər, -ˌwɒt ər /

noun

1. the salt water in or from the sea.

---

seawater Scientific  

/ sē′wô′tər /

1. Salt water, normally with a salinity of 35 parts per thousand (3.5%), in or coming from the sea or ocean. Although seawater contains more than 70 elements, most seawater salts are ions of six major elements: chloride, sodium, sulfate, magnesium, calcium, and potassium. The major sources of these salts are underwater volcanic eruptions, chemical reactions involving volcanic matter, and chemical weathering of rocks on the coasts. Seawater is believed to have had the same salinity for billions of years.

---

Etymology

Origin of seawater

before 1000; Middle English see water, Old English sǣwæter; see sea, water

Example Sentences

The taste of seawater drying on skin after a swim.

From Salon • Jun. 9, 2026

An internationally-important nature reserve faces "disaster" after being flooded by seawater because of failing coastal defences, conservationists have said.

From BBC • Jun. 4, 2026

“We’re proving a next-generation seawater desalination system that answers all of the concerns brought up by the environmentalists.”

From Los Angeles Times • Jun. 2, 2026

The technology harnesses that pressure to push seawater through reverse-osmosis membranes.

From Los Angeles Times • Jun. 2, 2026

Blinking against the stinging seawater, I watched as the spikes of rock shattered the stone hull.

From "City of the Plague God" by Sarwat Chadda