- an electric lamp made of a transparent, tapered cylinder containing a liquid in which a colored wax-based or waxlike substance is stimulated by the heat of the light bulb to change into randomly separating shapes that constantly rise and fall: Call me an old hippie, but lava lamps belong in rooms with Woodstock posters and beaded curtains, not among the pristine décor of gabled verandas.
- a decorative type of lamp in which a luminous viscous material moves in constantly changing shapes
