Fullness is the state of being filled up or complete. After a big Thanksgiving dinner, you might feel a pleasant fullness in your stomach, that satisfied sensation of having eaten just enough. A balloon reaches fullness when you've blown enough air into it but haven't overinflated it yet.

The word describes physical, sensory, and abstract completeness. A library can achieve fullness when every seat is taken by students studying. An orchestra plays with fullness when every instrument blends together to create a rich, complete sound. Artists talk about the fullness of a color when it's deep and vibrant rather than pale or washed out.

Fullness also describes emotional or spiritual completeness. Someone might describe the fullness of joy they felt at their sister's wedding, or the fullness of a moment when everything feels exactly right. When a writer captures the fullness of a character, they've shown us every important dimension of that person's personality.

The word suggests abundance and completion rather than excess. There's a difference between fullness and being overstuffed: fullness is that perfect point where nothing is lacking, but nothing is too much.