There are no direct synonyms for the name "Gaius Aurelius Valerius Diocletian" as it is a specific historical name of a Roman Emperor who ruled from 284 to 305 AD. However, certain terms related to the era and culture in which he lived can overlap or be associated with his name, such as "Roman Empire," "Late Antiquity," "Tetrarchy," or "persecution of Christians." In addition, certain historical figures or titles from the same period, such as Constantine the Great, Maximianus, or Augustus, may also be related or compared to Diocletian's reign and legacy.