A church key is called by that name primarily because of its original design, which resembled large, old-fashioned keys used for churches. The name then persisted and was applied to a similar tool even as its function evolved.
Initially, these devices were designed to open bottles by prying off caps or removing corks. Their distinctive appearance, mimicking the substantial, decorative keys often associated with churches or grand buildings, led to the adoption of the "church key" moniker.
Over time, as beverage packaging evolved, so did the tools used to open them. When beer cans with flat metal covers were introduced and widely marketed in the 1930s, a new type of opener was needed. These new tools were used to pierce triangle-shaped holes into the can's lid to allow for pouring. Despite the change in design and specific function—from prying caps/corks to piercing cans—the familiar and descriptive name "church key" was retained for these newer, often simpler, openers. Thus, the term continues to be used for various types of bottle and can openers today, carrying its historical association.
