Part of a church in which bells hang

One word substitute is Belfry.

Minaret: a slender tower, typically part of a mosque, with a balcony from which a muezzin calls Muslims to prayer.
Chapel: a small building or room used for Christian worship in a school, prison, hospital, or large private house.
Belfry: the part of a bell tower or steeple in which bells are housed.
Spire: a tapering conical or pyramidal structure on the top of a building, typically a church tower.