A bubble is a thin sphere of liquid, usually filled with air, that forms when you trap gas inside a film of soapy water or other liquid. When you blow bubbles with a wand, you're stretching that soapy film around the air from your breath until it seals into a perfect, shimmering ball that floats away.

Bubbles appear in many places: in boiling water, in carbonated drinks like soda, in foam on ocean waves, and even in your bath. The fizz in soda comes from tiny bubbles of carbon dioxide gas escaping from the liquid. When water boils, bubbles of steam rise from the bottom of the pot to the surface.

The word also describes situations where something grows artificially large and then collapses. An economic bubble happens when the price of something (like houses or stocks) rises far beyond its real value because everyone thinks they can sell it for more later. Eventually the bubble bursts, prices crash, and people lose money. The famous Tulip Bubble in 1600s Holland saw single tulip bulbs selling for more than houses before the market collapsed.

When something is described as bubble-like, it can mean fragile, temporary, or isolated from reality, like living in a bubble where you don't see what's really happening in the world around you.