- the act of undulating
- an undulating motion, as of a snake
- a wavy, curving form or outline, esp. one of a series
- Physics wave motion, as of light or sound, or a wave or vibration
- A regular rising and falling or movement to alternating sides; movement in waves.
- A wavelike form, outline, or appearance.
- One of a series of waves or wavelike segments.
From Latin undulatio