Rondeau - rondo
Be careful not to confuse the homophones 'rondo' and 'rondeau' - both pronounced RON-dow, IPA: /ˈrɒndəʊ/.
The word 'rondo' is used exclusively as the name of a musical form. In a rondo the first section, often referred to as the principal theme, alternates with sections each of which contains different musical material. A piece of music in rondo form thus has the structure ABACADA or some variant of this, i.e., the principal theme (A) is repeated rather like a refrain. See further Rondo.
The word 'rondeau' is the name of a verse form which originated in France in the Middle Ages and of the musical form which was developed to set poems in this verse form to music. The rondeau in this latter sense was the ancestor of the rondo. See further Rondeau.