US Military Branches
Military-Ranks.org provided me a bird's eye view—links to the US military branches and pay in the index at the left. At the rank or pay level, you can find out how the ranks vary within each branch. Clicking a branch's rank opens a page with more details of the role. Near the bottom, the Equivalent Ranks section links to the same rank across the branches in the following order: Air Force, Army, Coast Guard, Marines (listed as Marine Corps), Navy.
The US Department of Defense has pages with illustrated tables for all five branches for enlisted members and officers (Coast Guard & Navy combined). Curiously, Warrant Officer is notably absent in Air Force, which the DoD officers page shows as "NO WARRANT". In the Wikipedia page for Warrant Officer, the illustrated table shows insignias and grades for all five branches for warrant officers, with the Air Force column heading "discontinued".
Ranks of Interest—Spelling and Pronunciation
EnlistedRanks of Interest—Rank vs. Non-Military Context (E, enlisted; O, officer)
Sergeant [sahr-juhnt], from Latin root meaning "serve"
Officer
Ensign—Navy/Coast Guard [en-sahyn; Military en-suhn], pertinent to flag, insignia
Lieutenant [loo-ten-uhnt], pertinent to "placeholder"
Captain (kap-tuhn, -tin), pertinent to "head"
Colonel [kur-nl], related to "column"
The general topic
Soldier [sohl-jer]
- private (E), the member who has the lowest rank and probably least privacy
- major (O), no major in sea branches, no rank named "minor"
- petty officer (E), rank with "officer" in title, but not in either warrant of officer category
- lance corporal (E), visualizing a Renaissance Fair knight engaged in joust
- general (O), ordinarily meaning ordinary
During my research, "commander" stuck out as a rank I've heard more in reference to James Bond than American commanders. Commanders rank lower than captains. Captains of the sea rank higher than non-sea captains.
The US Navy and Coast Guard have commander ranks—commander and lieutenant commander—ranks that are just below captain. Captains in sea branches rank higher than captains in the other branches. A Yahoo discussion contrasts naval captain vs. army captain. Visit a Wikipedia page to view a table that compares US and British ranks, including "commander".