Roget's Thesaurus

#251. Flatness

Nouns

flatness etc. adj.; smoothness etc. 255. plane; level etc. 213; plate, platter, table, tablet, slab.

Verbs

render flat, flatten; level etc. 213.

Adjectives

flat, plane, even, flush, scutiform, discoid; level etc. (horizontal) 213; flat as a pancake, flat as a fluke, flat as a flounder, flat as a board, flat as my hand.