Ma' at
From Tardis Wiki, the free Doctor Who reference
Ma' at, also spelled Ma'at and Maat, was a concept in Egyptian mythology. It was the word for "truth" and "feather" in hieroglyphs. It regarded the order of the universe as well as "truth, justice, and the Egyptian way".
Ace had a funeral dream where the Seventh Doctor's hearts were weighed against ma’ at, an Ostrich feather. (PROSE: Set Piece)
Sadan Rassul and a Priest dressed as Anubis weighted a golden replica of a human heart against the feather that symbolised Maat. (PROSE: The Sands of Time)
Senbeb was considered a good man and his heart was expected to weigh lightly against the feather of Ma'at. (PROSE: The Water Thief)