Emily Dickinson Lexicon

NETH'ER, a. [Sax. neother; G. nieder; D. and Dan. neder. This word is of the comparative degree; the positive occurs only in composition, as in beneath, Sax. neothan. It is used only in implied comparison, as in the nether part, the nether millstone; but we never say, one part is nether than another.]

1. Lower; lying or being beneath or in the lower part; opposed to upper; as, the nether millstone. Distorted all my nether shape thus grew / Transformed. Milton.
2. In a lower place. 'Twixt upper, nether, and surrounding fires. Milton.
3. Belonging to the regions below. Dryden.