The Orthodox Cross
Three bars, one meaning — the theology of the three-barred cross.
The three bars
The top bar represents the titulus — the sign nailed above Christ's head by order of Pilate, bearing the inscription "Jesus of Nazareth, King of the Jews" in three languages (John 19:19–20). In Orthodox iconography it often carries the abbreviation INBI (Greek) or INTsI (Slavonic).
The middle bar is the horizontal beam on which Christ's hands were nailed.
The bottom bar is the suppedaneum, the footrest to which Christ's feet were affixed. In Orthodox iconography it tilts diagonally: the raised end points to Paradise, the lowered end to Hades. It marks the two thieves crucified with Him — the repentant thief to Christ's right, who was promised Paradise that very day (Luke 23:43), and the unrepentant thief to His left.
Why the tilted footrest
The slanted bar is not decoration but a sermon in wood. It preaches that the same Cross on which Christ was crucified became, in one moment, both the ladder of ascent and the seat of judgment — depending on which side of it one stood.
Not a rejection of the Latin cross
Orthodox Christians venerate every form of Christ's Cross, whether the simple two-barred Latin cross, the three-barred Slavonic cross, or the many crosses of Ethiopian, Armenian, and Coptic tradition. The three-barred cross is not "the" Orthodox cross to the exclusion of others, but it is the form most closely associated with the Russian and Slavic Orthodox world.