[stylin19a]

that's a heck of a question...I bet a lot of us do not know...

might be here Marines

Historically, marines serve as a navy’s ground troops. In fact, the word "marine" is the French word for sea, which may be why the French military historically called English troops — who all had to arrive by sea — "marines."

[Gulf War One]

There are problems with trying to translate the English term Marine because “marine” means sailor or navy in romance languages. In Spanish for example, they use the term “infantería de marina”, literally naval infantry. We don’t have that problem in English because we can use both “Marines” and “sailors” to distinguish between the forces.

[Cletus.D.Yokel]

:: why the French military historically called English troops — who all had to arrive by sea — “marines.” ::

I’m sure there was a “we surrender” in there, too.