thole

Philostratus relates that the king's house in Babylon had a roof of brass, which shone like lightning, and that in that house there was a chamber, whose ceiling was a thole (that is, a concave hemisphere) made in imitation of some system of the heaven, and with sapphire-coloured stones, […] and from the thole were suspended four golden doves, or iynges, who were called the Tongues of the Gods.