Definition of "unmounted"
Not mounted (in various senses).
Quotations
Official Railway Map of England and Wales, 1947. […] Railway Clearing House […] This map is available in unmounted sheets (four sections at £1 10s.); mounted on linen, dissected, folded, and with Rexine cover, £2 5s.; and mounted on linen, varnished, on rollers as a wall map, £2 6s.
1948 May and June, “Railway Literature”, in Railway Magazine, pages 210–211