In Halo 3: ODST, what does the abbreviation ODST stand for?

In Halo 3: ODST, ODST stands for Orbital Drop Shock Trooper.

ODSTs are elite human soldiers who deploy from orbit in specialized drop pods. Their missions are particularly dangerous because the troops enter combat without the powered armor and extensive biological enhancements used by Spartans.

Halo 3: ODST follows a squad of these soldiers during the Covenant occupation of New Mombasa. Instead of playing as Master Chief, the player takes the role of an unnamed Rookie and later controls other members of the squad during the campaign.

The term is sometimes mistaken for the name of the game’s protagonist or for a military unit’s informal nickname. It is actually the formal expansion of the acronym describing the soldiers. The phrase “Orbital Drop Shock Trooper” highlights both their method of deployment and their role as shock infantry.