Well
haline is derived from Greek and
saline is derived from Latin. Otherwise they seem to mean exactly the same thing. A
halogen is an element that can form a salt by combining with a metal.
The word
haline is in Wiktionary but no other dictionary that I can see, but scientists do sometimes use it. For example in
Nature in February 2021:
The influence of salinity changes has also been a central focus of studies on estuarine ecosystem biodiversity, which is commonly reduced along haline gradients from marine to brackish conditions.
I'll add it as a rare word.
