1) Devil dog 2) Marine 3) Us marine 1) GI Joe character 2) Devil dog 3) Man in uniform, slang 4) Marine 5) Military man 6) Military personnel 7) Serviceman 8) Shipboard soldier 9) Third-year Marine 
Leatherneck is a military slang term for a member of the United States Marine Corps. ==Etymology== The term `leatherneck` was derived from a leather stock once worn around the neck by both American and British marines. Beginning in 1798, `one stock of black leather and clasp` was issued to each marine annually. Its use as a synecdoche for Mari...
• (n.) The sordid friar bird of Australia (Tropidorhynchus sordidus).
(from the article `United States Marine Corps, The`) ...collar, is well known. From the standing collar—descended from the tall leather neckpiece of the 18th- and 19th-century uniform—comes the ...
Naval Another naval slang name for a Royal Marine; it is derived from the small piece of leather sewn in the collar of the Marines' dress tunic. A synonym is 'Bootneck'. 
Leath'er·neck` noun (Zoology) The sordid friar bird of Australia ( Tropidorhynchus sordidus ). 
Leatherneck is slang for a member of the U.S. Marine Corps.
antiquated nickname for Marine, so named for legends stating that stiff leather collars were once worn to protect the throat from sword-blows (also thought that high stocks were worn for discipline, to keep Marines' heads high and straight). The dress blue uniform still bears a high stock collar today. Also, Leatherneck Magazine.