shellac

US /ʃəˈlæk/
UK /ʃəˈlæk/
1.

đánh gôm lắc

a substance obtained from an insect that is melted into small thin pieces and used for making varnish (= a liquid for painting onto surfaces to make them shiny) and for many other purposes:

:
The pottery is covered with a layer of varnish or shellac.