#undulation__wave  (physics) a progressive disturbance propagated without displacement of the medium itself
  supertype:  periodic_event__recurrent_event__recurrentevent  an event that recurs at intervals
  part:  wave_front
  subtype:  gravity_wave__gravitywave__gravitation_wave__gravitationwave  (physics) a wave that is hypothesized to propagate gravity and to travel at the speed of light
  subtype:  sine_wave  a wave whose waveform resembles a sine curve
  subtype:  vibration__oscillation  (physics) a regular variation in value about a mean
     subtype:  ripple  (electronics) an oscillation of small amplitude imposed on top of a steady value
     subtype:  transient  (physics) a short-lived oscillation in a system caused by a sudden change of voltage or current or load
     subtype:  beat.vibration  a single pulsation of an oscillation produced by adding two waves of different frequencies; has a frequency equal to the difference between the two oscillations
     subtype:  resonance.vibration  a vibration of large amplitude produced by a relatively small vibration near the same frequency of vibration as the natural frequency of the resonating system
     subtype:  sympathetic_vibration__sympatheticvibration  (physics) vibration produced by resonance
  subtype:  fluctuation  a wave motion; "the fluctuations of the sea"
  subtype:  seiche  a wave on the surface of a lake or landlocked bay; caused by atmospheric or seismic disturbances
  subtype:  standing_wave__stationary_wave  a wave (as a sound wave in a chamber or an electromagnetic wave in a transmission line) in which the ratio of its instantaneous amplitude at one point to that at any other point does not vary with time
  subtype:  sound_wave__soundwave__acoustic_wave  (acoustics) a wave that transmits sound
     subtype:  air_wave__airwave  a sound wave that is transmitted via air
     subtype:  shock_wave__shockwave  a region of high pressure travelling through a gas at a high velocity
        subtype:  sonic_boom__sonicboom  an explosive sound caused by the shock wave of an airplane traveling faster than the speed of sound; "a sonic boom follows an aircraft as a wake follows a ship"
  subtype:  waveform__wave_form__wave_shape  the shape of a wave illustrated graphically by plotting the values of the period quantity against time
  subtype:  pulsing__pulse__impulse  (electronics) a sharp transient wave in the normal electrical state (or a series of such transients); "the pulsations seemed to be coming from a star"
  subtype:  flapping__flap__flutter__fluttering  the motion made by flapping up and down

No statement uses or specializes undulation; click here to add one.