Emily Dickinson Lexicon

FLAT'NESS, n.

1. Evenness of surface; levelness; equality of surface.
2. Want of relief or prominence; as, the flatness of a figure is sculpture. Addison
3. Deadness; vapidness; insipidity; as, the flatness of cider or beer. Mortimer.
4. Dejection of fortune; low state. The flatness of my misery. Shak.
5. Dejection of mind; a low state of the spirits; depression; want of life. Collier.
6. Dullness; want of point; insipidity; frigidity. Some of Homer's translators have swelled into fustian, and others sunk into flatness. Pope.
7. Gravity of sound, as opposed to sharpness, acuteness or shrillness. Flatness of sound – joined with a harshness. Bacon.