We don't have synonyms for coping stone yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are bowing stone and coping stones.
°A ceremonial stone set at the corner of a building, joining two exterior walls, and often inscribed with the starting and completion dates of construction, the name of the architect and owner, and other details.
"The cornerstone on the Flatiron Building is set on the Fifth Avenue facade."
°A ceremonial stone set at the corner of a building, joining two exterior walls, and often inscribed with the starting and completion dates of construction, the name of the architect and owner, and other details.
"The cornerstone on the Flatiron Building is set on the Fifth Avenue facade."