What is "sheshet"

Rav Sheshet ( Hebrew: רב ששת) was a Babylonian amora of the third generation and colleague of R. Naḥman bar Jacob, with whom he had frequent arguments concerning questions of religious law. His teacher's name is not definitely known, but Sheshet was an auditor at Huna's lectures ( Yeb. 64b; Ket. 69a). The name is sometimes pronounced Shishat.