Hooah / Oorah / Hooyah

These expressions serve as universal affirmatives, expressions of enthusiasm, and responses to almost anything. Army: 'Hooah' (origin uncertain, possibly from 'HUA', Heard, Understood, Acknowledged). Marines: 'Oorah' (likely from a Korean War-era call). Navy surface sailors tend to avoid the terms; Navy SEALs and Coast Guard use 'Hooyah.' Air Force/Space Force use 'Hooah' in joint settings but have no official equivalent. Using the wrong branch's expression is a common mistake.