Tau Cross was shaped in the form of a “T,” and is an ancient symbol of eternal life. The Druids venerated and made a tree sacred by etching into its barn a tau cross. Among Christians it is hailed as the “Cross of St. Anthony” since the saint was allegedly martyred on such a cross. The tau cross is utilized in Freemasonry as one of its symbols. A.G.H.
Source: 2, 297-298