Marine means to do with the sea. Marine life, marine biology, a marine engine.
It covers the sea itself where maritime covers seafaring and naval covers the navy, which is a three-way split worth keeping. As a noun a Marine is a soldier serving with a navy. Note that the Latin mare means the sea, the same root as maritime and mermaid.
1adjectivemarineTo do with the sea.
“Plastic in the oceans is a serious danger to marine life.”
marine is a quality of relating to the sea.
Latin marinus comes from mare, the sea. Maritime, mariner and mermaid come from the same sea.
Middle English
marin
English, today
marine
Built from
From Middle English marin. Recorded since c.1420 as Middle English marin, borrowed from Middle French marin, from Old French -, from Latin marinus (“of the sea”), itself from mare (“sea”), from Proto-Indo-European móri (“body of water, lake”) (cognate with Old English mere (“sea, lake, pool, pond”), Dutch meer, German Meer, all from Proto-Germanic mari). The modern pronunciation is presumably due to the influence of modern French marine, feminine singular of marin.
Etymology from Wiktionary, CC BY-SA