a T-shaped cross, in which the horizontal bar lies on top of the upright; cf. sense 1a.

a cross without a head or top part; a T-shaped cross; = tau cross n. at tau, n. compounds 3.

Of a cross: having the form of a tau; T-shaped. Cf. tau cross n. at tau, n. compounds 3. Only in cross commisse.

A mark, sign, or figure in the shape of the Greek letter tau (see sense 2); esp. such a figure as a Christian symbol considered as prefiguring or…