nether (adj.)

Middle English lawar, lower, lougher, earlier lahre (c. 1200), comparative of lah "low" (see low (adj.)). As an adverb from 1540s. Lower-class is from 1772. Lower 48, "the forty-eight contiguous states of the United States of America, excluding Alaska and Hawaii," is by 1961 in an Alaska context (Hawaii actually is "lower" on the globe than all of them).

Middle English binethe, from Old English beneoðan "under, below, in a lower place, further down than," in late Old English "lower in rank, degree, excellence, etc.," from be- "by" + neoðan "below, down, from below," from Proto-Germanic *niþar "lower, farther down, down" (see nether).

The meaning "unworthy of" is attested from 1849 (purists prefer below in this sense). "The be- gave or emphasized the notion of 'where,' excluding that of 'whence' pertaining to the simple niðan" [OED].