the GNU version of the Collaborative International Dictionary of English
n. A stone laid over, or erected near, a grave, usually with an inscription, to preserve the memory of the dead; a tombstone.
The Century Dictionary and Cyclopedia
n. A stone laid over a grave, or erected near it (commonly at its head), in memory of the dead.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. a stone that is used to mark a grave
Word Usage
"In the north especially the grave is very often surmounted by a huge marble tortoise bearing the inscribed tablet, or what we call the gravestone, on its back."