preposition
(especially AmE) (old-fashioned or literary in BrE) on top of; at the top of:
a flag high atop a pole * a scoop of ice cream atop a slice of apple pie * The children piled atop one another in the sand. * Fruit and vegetable prices rose 1.3 per cent atop a 2 per cent gain last month. * Coca-Cola is atop the list of best-selling soft drinks in the US.
