This is the 1308th most frequent French word.
fer
Iron.
In this sentence, 'fer' refers to 'horseshoes', which are made of iron (fer in French).
Le cheval portait de nouveaux fers que le maréchal lui avait donnés.
The horse wore new shoes that the blacksmith had given him.
Here, 'fer' is used to mean 'iron', the appliance for ironing clothes, directly derived from its material.
Marie a placé un fer chaud sur son linge pour le repasser.
Marie placed a hot iron on her laundry to iron it.
'Fer' in this context refers to 'iron', a type of metal used in construction.