What is the meaning of Spall?

A splinter, fragment or chip, especially of stone.

A process of weathering, aging, or other wear that involves the crumbling of the substrate.

To break into fragments or small pieces.

To undergo weathering, aging, or other wear that involves the crumbling of the substrate.

To reduce, as irregular blocks of stone, to an approximately level surface by hammering.

The shoulder.

Source: wiktionary.org