From Longman Dictionary of Contemporary Englishtinfoiltin‧foil /ˈtɪnfɔɪl/ noun [uncountable] DFCthin shiny metal that bends like paper and is used for covering food
Examples from the Corpus
tinfoil• A length of yarn to cut into four equal pieces, and besides that, some white silk thread and tinfoil.• There are no pieces of tinfoil or wraps of cling-film here.• Even so, the Graphophone mouthpiece was not much more sensitive than that of the tinfoil phonograph. 