The Collaborative International Dictionary of English v.0.48:

Osar \O"sar\, n. pl. (Geol.)
   See 3d Os.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

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]

V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

OSAR
       Optical Storage and Retrieval