mass of sediments scraped off from oceanic crust during subduction and piled up at the edge of the overriding plate. Also called an accretionary prism.

Sediments, the top layer of material on a tectonic plate, that accumulate and deform where oceanic and continental plates collide. These sediments are scraped off the top of the downgoing oceanic crus [..]

Pile of sediments, characterized by repeated thrust faults, which accumulates on the oceanward side of a subduction zone. It grows due to sediment being scraped off the descending plate at a subductio [..]

 (prism)

A large wedge-shaped mass of sediment and oceanic lithosphere. An accretionary wedge forms along a convergent plate boundary when material is scraped from a sinking, subducting plate and is added to (accreted) another larger plate along a convergent plate boundary.