Lewis Short
tau (noun N) :
* The name of the Greek T, Aus. Idyll. Lit. Monos. 18: et signa tau super frontes virorum gementium,Vulg. Ezech. 9, 4 (al. thau).
Charlton T. Lewis, Charles Short, A Latin Dictionary
Lewis Short
tau (noun N) : a Celtic word of unknown meaning, Verg. Cat. ap. Quint. 8, 3, 28; cf. Aus. Idyll. 12, 6.
Charlton T. Lewis, Charles Short, A Latin Dictionary