Meaning

noun an enlisted man or woman who serves in an army

noun a wingless sterile ant or termite having a large head and powerful jaws adapted for defending the colony

verb serve as a soldier in the military

originInherited from Middle English soudeour, from Old French soudier or soudeour (“mercenary”), from Medieval Latin soldarius (“soldier (one having pay)”), from Late Latin solidus, a type of coin. Displaced Old English cempa (whence obsolete kemp). (red herring): An allusion to soldiers' red uniforms; red herring is, reciprocally, a slang term for "soldier".

Etymology from Wiktionary, CC BY-SA 3.0