Etymology: belfry
The word belfry comes from Old French berfrei which is derived from Germanic *bergan "to protect" and *frithuz "peace"; that is, it was originally a watch tower providing protection against hostile incursions. In larger towns, watchmen in these towers were also on the lookout for fires. Though flags were used by the watchmen for communication, these towers usually contained an alarm bell or bells built into a Bell-Cot, thus Middle English speakers thought berfrei had something to do with bells: they altered it to belfry, an interesting example of the process of folk etymology. Today's Dutch belfort seems to combine the term "bell" with the term "stronghold", while the Dutch term klokkenstoel (bell-chair) refers only to the construction of the hanging system, or the way the bell or bells are installed within the tower.
Read more about this topic: Bell Tower