A few dozen Roman Catholic cardinals are sequestered in the Sistine Chapel, as I write, taking part in the papal conclave. I'm not sure whether they are actually locked in, but that is the literal meaning of the word 'conclave'. Con is the combining form of the Latin word for 'with', cum, and clavis is Latin for 'key'.
The English music-related words claviature and clavichord are also derived from clavis, as is the word clavicle, or collar-bone. The OED tells us that the 19th-century French lexicographer Littré explained that some people said the collar-bone was compared to the key of a vault, while others said it resembled old bolts in form.
Here's a BBC piece giving ten facts about the conclave.