Other forms: shellacs
You might paint a layer of shellac, or varnish, on a bench built from reclaimed and stained wood, to protect it and give it a glossy sheen.
This noun, mainly associated with a thin varnish, displays its origins plainly: the main ingredient is lac, a resinous substance secreted by some scale insects. Shellac started making the rounds in English in the 18th century and enjoyed a vogue a century later as the main constituent of phonograph records. It originally came from the French laque en écailles, or "lac in thin plates."