1. (adj)undulate having a wavy margin and rippled surface
2. (verb)ripple, ruffle, riffle, cockle, undulate stir up (water) so as to form ripples
3. (verb)roll, undulate occur in soft rounded shapes
"The hills rolled past"
4. (verb)roll, undulate, flap, wave move in a wavy pattern or with a rising and falling motion "The curtains undulated"; "the waves rolled towards the beach"
5. (verb)undulate increase and decrease in volume or pitch, as if in waves
"The singer's voice undulated"