'monarch' originates from Greek, specifically the word 'monarkhēs,' where 'monos' meant 'alone' and 'arkhein' meant 'to rule.'

'monarkhēs' transformed into the Latin word 'monarcha,' and eventually became the modern English word 'monarch' through Old French.

Initially, it meant 'sole ruler,' but over time it evolved into its current meaning of 'sovereign head of state.'