Obelisks as Memorials: The definition of obelisk is provided by Merriam-Webster (headquartered in nearby Springfield): "a tall, four-sided stone column that becomes narrower toward the top and that ends in a point." Look carefully at this memorial pillar. Is it an obelisk? Or is it a daughter product of stimulus diffusion? A tapering hexagonal prism crowned by a hexagonal pyramid. North Cemetery.