ˈɹʌfəl ˈʌndjəleɪt ˈʌndjəleɪt increase and decrease in volume or pitch, as if in waves The singer's voice undulated move in a wavy pattern or with a rising and falling motion The curtains undulated the waves rolled towards the beach stir up (water) so as to form ripples having a wavy margin and rippled surface occur in soft rounded shapes The hills rolled past