Definition of "tin-foil" [tin-foil]

• Thin sheet-metal or thick foil either of pure tin or of an alloy of which tin forms the greater part: used for wrapping up articles, such as drugs and confectionery, which must be kept from moisture or from the air. (noun)
• To cover with tin-foil; fix tin-foil upon as a coating. The tin-foiling of looking-glasses is commonly called silvering. See silver, v. t., 2.

The Century Dictionary (Public Domain)

• "Bolling wore a tin-foil hat and nerdy glasses, and held a sign reading "Occupy The Five.""
• "Better adjust your tin-foil hat your crazy talking points aren't coming in too clearly."
• "If you don't want to be any better than everyone else in their tin-foil hats - have at it - but that's your choice."