The quality or state of being flat.
- The state of being flat
- The state of being two-dimensional; planar : planarity
- The state of being bland : dullness
- Mattness, the quality of a painted surface which scatters or absorbs the light falling on it, so as to be substantially free from gloss or sheen
- Lack of bouquet and freshness of a wine, through too much aeration or infection with film yeasts
- Sometimes used as a synonym for slim-tailedness or platykurticity