Diocletian window

A semicircular window with two mullions, also known as a thermal window. So called because of its use in the Roman baths – or thermae – built by the emperor Diocletian at the end of the third century AD.

'Mackintosh Architecture' led by The Hunterian, University of Glasgow, funded by the Arts and Humanities Research Council; with additional support from The Monument Trust, The Pilgrim Trust, and the Paul Mellon Centre for Studies in British Art; and collaborative input from Historic Scotland and the Royal Commission on the Ancient and Historical Monuments of Scotland.