shel ‧ lac /ʃəˈlæk/ BrE AmE noun [uncountable]
[ Date: 1600-1700 ; Origin: shell + lac 'hard substance produced by an insect' (15-21 centuries) (from Portuguese laca ; ⇨ ↑ lacquer 1 ), translating French laque en écailles 'lac in thin flakes' ]
a type of transparent paint for protecting or hardening surfaces