zyl
Also called zylonite, zylo
Abbreviation of zylonite, an early celluloid (cellulose-nitrate) plastic prized for its mirror polish yet infamous for igniting with heat. The nickname now covers most “plastic” frames, almost all milled from safer, plant-based cellulose acetate that is light, vividly dye-able, and easily heat-adjusted around 120 °C for fitting.