The full form of RTO can vary based on the context, but two common meanings are:
Regional Transport Office: In India, this is a government office responsible for the registration of vehicles, issuance of driving licenses, and enforcement of road transport laws.
Recovery Time Objective: In the context of IT and disaster recovery, this refers to the maximum acceptable amount of time that a system can be down after a failure occurs before it is restored to normal operations.
If you have a specific context in mind, please let me know!