Flatness

Full definition of flatness

(uncountable)

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
(oenology) Lack of bouquet and freshness of a wine, through too much aeration or infection with film yeasts
(statistics) Sometimes used as a synonym for slim-tailedness or platykurticity