Yes, marines like using a term that separates them from another group, because of a classification that the US military makes. Good for them! But, as a matter

Yes, marines like using a term that separates them from another group, because of a classification that the US military makes. Good for them! But, as a matter of actual common usage, which long pre-dated them, the term "soldier" has a more general meaning, which definitely applies here: 2. (by extension, nonstandard) Any member of a military, regardless of specialty. 3. An enlisted member of a military service, as distinguished from a commissioned officer. They even meet the primary definition except for the classification (also arbitrary) of being sea-based rather than land-based. 1. A member of a ground-based army, of any rank, but especially an enlisted member. https://en.wiktionary.org/wiki/soldier https://en.wiktionary.org/wiki/soldier If you're not actually interested in the petty rivalry, "soldier" communicates a correct understanding here.