Tsars are rulers of the Russian empire. Some people also spell it as 'czar', which comes from the word 'Caesar'. Synonyms for 'tsar' include 'emperor', 'king', 'monarch' and 'sovereign'. In Russian, tsar translates to 'tsar'' or 'tzar', which means 'supreme ruler'. In some cases, it can also refer to a powerful leader in general, without the association with the Russian empire. Other words like 'autocrat', 'dictator', and 'tyrant' can also be used as synonyms for 'tsar' in certain contexts. However, the use of these synonyms might carry negative connotations that do not apply to all tsars.