There are multiple origins and translations for the name Sebastian:
1. Derived from the ancient Greek word (σεβαστός) [thebathtos] which actually means - "high, holy; venerable". The epithet of the Roman emperors.
2. Comes from the Latin (Roman) name which actually means - "from Sebastia (Roman Armenian city)".
St. Sebastian was born at Narbonne, Gaul. He became a soldier in the Roman army at Rome in about 283, and encouraged Marcellian and Marcus, under sentence of death, to remain firm in their faith.