n. A little or thin skin; a cuticle; a film; a scum: as, the nacreous pellicle of some shells; the coaly pellicle of many fossil plants; the filmy pellicle or scum of infusions in which infusorial animalcules or microscopic fungi develop.n. In chem., a thin crust formed on the surface of saline solutions when evaporated to a certain degree. This pellicle consists of crystallized saline particles.n. In botany, same as cortical layer (Which see, under cortical)n. In entomology, the skin of the subimago of an ephemerid.