A large slab of stone laid over a tomb or grave; a horizontal gravestone; (also) a funeral monument consisting of a horizontal slab supported on columns; a table tomb.
Late Middle English; earliest use found in Cursor Mundi: a Northumbrian poem of the 14th century. From through + stone.
A stone or brick extending through the breadth of a wall (now especially a drystone wall) to bind or strengthen it, and often projecting on either side; a bondstone.
Late 18th century; earliest use found in John Bailey (1750–1819), mathematician and land surveyor. In some forms from through- + stone.