Dictionary.com
Thesaurus.com

lava lamp

American  
[lah-vuh lamp] / ˈlɑ və ˌlæmp /

noun

  1. 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.
lava lamp British  

noun

  1. a decorative type of lamp in which a luminous viscous material moves in constantly changing shapes

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of lava lamp

First recorded in 1965–70

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.