A warrant officer is an officer in the navy created by a warrant as opposed to commissioned officers created by commissions. Commissioned officers are lieutenant, commander, captain, admiral.
Warrant officers were below commissioned officers, above crewmen ranks such as seaman.
Senior warrant officers were the ship's master, surgeon, and purser; standing warrant officers were the boatswain, carpenter, and gunner.
midshipmen were classified as warrant officers.
Except for midshipmen, most warrant officers were crewmen who have risen from the lower ranks.
- Warrant Officer at Wikipedia