The Collaborative International Dictionary of English v.0.48:
Pieta \Pi*e*t[`a]"\ (p[-e]*[asl]*t[aum]"), n. [It.] (Fine Arts) A representation of the dead Christ, attended by the Virgin Mary or by holy women and angels. --Mollett. [1913 Webster]WordNet (r) 3.0 (2006):
pieta n 1: a representation of the Virgin Mary mourning over the dead body of Jesus