The Rolls-Royce Trent 900 is the Rolls-Royce jet engine used on the Airbus A380. It is a high-bypass turbofan designed specifically for the superjumbo and competes with the Engine Alliance GP7200, another engine option for the aircraft.
The Trent 900 belongs to Rolls-Royce’s Trent family and retains its distinctive three-shaft architecture. Its development was offered for the Airbus A3XX project, which became the A380 after its launch in December 2000. The engine first ran on 18 March 2003 and later flew aboard an Airbus A340 testbed.
The answer is sometimes confused with the RB211, Trent 1000 or Trent XWB because all are Rolls-Royce aircraft engines. They serve different applications: the Trent 1000 powers the Boeing 787, while the Trent XWB was developed for the Airbus A350. The A380 itself can also use the GP7200, so Trent 900 is the correct Rolls-Royce-specific answer.