M.E. lah (mid-12c.), from O.N. lagr "low," from P.Gmc. *lægaz (cf. O.Fris. lech, Du. laag, Ger. läge "low"), lit. "that which is lying flat;" related to O.E. licgan (see lie (v.)). Meaning "humble in rank" is from c.1200; "undignified" is from 1550s; sense of "dejected, dispirited" is attested from 1737. In reference to sounds, it is attested from early 15c. In geographical usage, it refers to the part of a country near the sea-shore (c.1300; cf. Low Countries "Holland, Belgium, Luxemburg," 1540s).
mid-13c., from O.Fr. humble, earlier humele, from L. humilis "lowly, humble," lit. "on the ground," from humus "earth." Senses of "not self-asserting" and "of low birth or rank" were both in M.E. Related: Humbly; humbleness.