n. The prepared location for a road, including its foundation.
the GNU version of the Collaborative International Dictionary of English
n. In railroads, the bed or foundation on which the superstructure (ties, rails, etc.) rests; in common roads, the whole material laid in place and ready for travel.
The Century Dictionary and Cyclopedia
n. The bed or foundation on which the superstructure of a railway rests.
n. The whole material laid in place and ready for traffic in ordinary roads.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. a bed supporting a road
Word Usage
"Unfortunately the roadbed is very poor, so the new repairs deteriorate rapidly."