corrugated board

Packaging material formed by gluing one or more fluted sheets of paperboard (corrugating medium) to one or more flat sheets (called facings) of linerboard. Its comes in four common types: (1) Single face: one fluted sheet glued to one facing (total two sheets). (2) Single wall: one fluted sheet sandwiched between two facings (total three sheets); also called double face or single ply. (3) Double wall: one single-face glued to one single wall so that two fluted sheets are alternatively sandwiched between three flat sheets (total five sheets); also called double cushion or double ply. (4) Triple wall: two single-face glued to one single wall so that three fluted sheets are alternatively sandwiched between four flat sheets (total seven sheets); also called triple ply. See also flute.