Os

Os Os, n.; pl. {Osar}. [Sw. [*a]s ridge, chain of hills, pl. [*a]sar.] (Geol.) One of the ridges of sand or gravel found in Sweden, etc., supposed by some to be of marine origin, but probably formed by subglacial waters. The osar are similar to the kames of Scotland and the eschars of Ireland. See {Eschar}. [1913 Webster]