The Spanish word 'república' (meaning 'republic') comes from the Latin phrase 'res publica', which literally meant 'public matter' or 'public affair'. This Latin phrase was formed by combining two words: 'res' meaning 'thing' or 'matter', and 'publicus' meaning 'of the people'. Over time, this concept evolved to specifically refer to a form of government where power rests with the people and their elected representatives, giving us the modern Spanish word 'república'.

Some related Spanish words include 'público' (public), 'publicar' (to publish), and 'publicidad' (advertising) - all of which share the Latin root 'publicus' and relate to things involving or serving the people.

English speakers can easily connect 'república' to the English word 'republic', which shares the same Latin origin. Other related English words include 'public', 'publish', and 'publicity' - all derived from Latin 'publicus'. The connection between these words lies in their relationship to matters concerning the general population or things that are openly accessible to people.