What does "compo" mean?

Compo: Short for Composition; -- used, esp. in England, colloq. in various trade applications; as : (a) A mortar made of sand and cement. (b) A carver's mixture of resin, whiting, and glue, used instead of plaster of Paris for ornamenting walls and cornices. (c) A composition for billiard balls. (d) A preparation of which printer's rollers are made. (e) A preparation used in currying leather. (f) Composition paid by a debtor.