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1. Stir up (water) so as to form ripples
   - ripple, ruffle, riffle, cockle
    
2. Occur in soft rounded shapes
   "The hills undulated past"
   - roll
    
3. Move in a wavy pattern or with a rising and falling motion
   "The curtains undulated"
   - roll, flap, wave
    
4. Increase and decrease in volume or pitch, as if in waves
   "The singer's voice undulated"

1. Having a wavy margin and rippled surface

Derived forms: undulated, undulates, undulating

See also: smooth, undulation

Type of: change, flow, flux, move

Encyclopedia: Undulate