Warrant officers held their positions by virtue of a warrant. Depending on the service, that authority came from a ministry, the Admiralty, the army, or a regiment, rather than a commission from the Crown. Petty officer derives from a French word meaning small or minor, adapted in medieval England for a very low-ranking officer. Chief petty officer retains that same term for a subordinate officer within its longer title.
Chapter · 7:43-9:15
Warrant appointments and the meaning of petty officer
A warrant identifies the authority behind an appointment, while petty officer preserves an older term for a small or minor officer.