Belfry comes from Old French berfrei ('movable siege tower'), from a Germanic compound *bergfrid, literally 'protecting shelter' (berg- 'to protect' + frid 'peace, shelter'). The form was altered by association with bell, and the meaning shifted to 'bell tower'. The historical trail runs through berfrei in Old French and *bergfrid in Proto-Germanic. Morphologically, belfry is transparent: it draws on Old French berfrei ('movable siege tower'), from a Germanic compound *bergfrid, literally 'protecting shelter' (berg- 'to protect' + frid 'peace, shelter'). Used as a noun, belfry now means "a bell tower or the part of a tower housing bells", so the present definition can be read against the older forms and meanings. The result is a borrowed or transmitted form whose modern spelling carries a compact record of its route into English.