a state whose head is not a monarch and in which supreme power resides in the people and is exercised by their elected representatives governing according to law
The word ‘republic’ derives from the Latin res publica, meaning ‘state’. Today it more commonly means a form of government in which the head of state is appointed or elected, as opposed to monarchy, in which the head of state is hereditary. The term may also refer to a style of politics – ‘republican’, emphasizing political participation and public spirit — Professor Vernon Bogdanor
[French république from Latin respublica, from res thing, wealth + publica, fem of publicus: see public1]