Lightness is the quality of weighing very little or appearing pale and bright in color. A balloon has lightness because it weighs almost nothing and floats easily in the air. A feather demonstrates perfect lightness as it drifts slowly to the ground instead of dropping like a rock.

The word also describes brightness in color. A room painted in light shades, like cream or pale blue, feels open and airy. Artists think about the lightness or darkness of colors when they paint: a light yellow is closer to white, while a dark yellow is closer to orange or brown.

Beyond physical weight and color, lightness can describe a cheerful, carefree quality in how someone acts or feels. When you finish your last final exam before summer vacation, you might feel a wonderful lightness, as if a heavy backpack has been lifted off your shoulders. A comedian brings lightness to a serious situation with a well-timed joke. Ballet dancers seem to move with impossible lightness, as though gravity barely affects them.

The opposite of lightness is heaviness or darkness, whether you're talking about weight, color, or mood. Something done “with a light touch” means done carefully and gently, without being harsh or heavy-handed.