A tower or other erection for containing a bell or set of bells; a belfry; sometimes regarded as referring spec. to a detached structure, but…

A bell-tower or campanile; a belfry.

A bell-tower; generally attached to a church or other building, but sometimes standing separate.

A bell-tower; esp. applied to the lofty detached bell-towers of Italy; a steeple generally.

a gable or turret in which bells are hung.

attributive, as in belfry-key, belfry-stage, belfry-tower, belfry-window.