noun piece of rolled up silver foil used as a filter in marijuana pipes. The 'gerrick' is made by laying out a piece of foil (usually from a cigarette box), or thin cardboard (usually from the same box) into a square, rolling it up, bending it into a circle and wedging it into the bottom of a bottleneck pipe to keep the marijuana from falling out when the smoke is sucked in SOUTH AFRICA, 2003