(Italian, from Latin sanctus, "saint", or saccus, "sack" + Benito, Italian form of Saint Benedict's name).
A yellow sack-like dress, with a red cross of Saint Andrew (i.e. an X-like cross) on the front and back. Worn by those condemned for heresy by the Inquisition, in their rôle as penitents - usually combined with a conical hat, like a dunce's cap.
Condemned heretics who refused to recant their heresy wore a similar garment on their way to execution, except that this was black, and decorated with demonic figures and flames (of Hell).
The origin of the name is presumably from the similarity of the garment to the scapular of Saint Benedict.