Shellac is a clear paint product similar to varnish. From Wikipedia -- Shellac is a resin secreted by the female lac bug, on trees in the forests of India and Thailand. It is processed and sold as dry flakes and dissolved in ethanol to make liquid shellac, which is used as a brush-on colorant, food glaze and wood finish.
Also from Wikipedia -- Varnish is a transparent, hard, protective finish or film that is primarily used in wood finishing but also for other materials. Varnish is traditionally a combination of a drying oil, a resin, and a thinner or solvent.