• verb:   increase and decrease in volume or pitch, as if in waves

  Example: "The singer's voice undulated"

• verb:   occur in soft rounded shapes
• verb:   move in a wavy pattern or with a rising and falling motion

  Example: "The curtains undulated"

• verb:   stir up (water) so as to form ripples
• adjective:   having a sinuate margin and rippled surface

Related words...