An old Commentary on the Tipitaka, used by Buddhaghosa in the compilation of his works.
It is often referred to in the Samantapásádika and its comments quoted.
Tradition has it that it was so called because it was compiled on a raft. E.g., Sp.i.283; iii.527, 536, 553, 615; iv. 763, 770, 776, 778, 782, 803, 806, 807, 813, 861, 914, 923, etc.