Outlined Greek cross is a symbol that consists of a heavy black cross and a thin frame bigger than the central structure. The frame casts a bit further that the cross, and due to such design, the symbol looks three-dimensional and bulky.  

Crosses with even rectangular bars, which are perpendicular to each other, are often called Greek. Unicode has more symbols denoting this Christian phenomenon. For example, [U:271A] heavy Greek cross, [U:271C] heavy open centre cross. Despite the sacred origins, the use of such symbols is not restricted to the religious context.