A tin box, or tin (in American English) is a metal box with a recloseable lid, which sometimes is hinged to the rest of the box. (It seldom involves more tin than a thin plated layer whose purpose is to inhibit corrosion.) In some cases the lid is held in place, when closed, by friction; in others, two protruding parts can pass each other only when the lid and the rest of the box are deformed slightly: pressure from the user's hands is sufficient to produce this deformation, while the parts resist this somewhat, and are flexible enough to recover their normal shape when released.`

Modern tin boxes have been used to hold items such as breath mints, throat lozenges, instant coffee, cocoa and even CD-ROMs for an internet service provider. In the past even more products were stored in tins, many highly decorated. Businesses tried to encourage the re-use of tins they provided, with the effect of the tins advertising them. One common use of the tin was as a children's lunchbox and in the UK as biscuit tins.