seawater; sea water; saltwater from the sea
Refers specifically to naturally salty water from the sea or ocean. Although it can be translated as “saltwater,” artificially salted water is more often 塩水.
海水を飲むと、かえって喉が渇く。
If you drink seawater, you actually get thirstier.
この魚は海水で育つ。
This fish grows in seawater.
The seawater at this beach is cold and clear.
I got swept by a wave and swallowed some seawater.
My shoes got soaked in seawater and became covered in salt.
I scooped up seawater with a bucket and put it in the tank.
bathing cap; swim cap
sea level