Apotropaic

The horseshoe brings luck and has apotropaic meaning.

Wormwood [...] was associated with the rites of St. John's Eve, when a crown of the plant was made from its sprays for apotropaic purposes, to ward of malefic spirits.

A boring subtext, about the wisdom or otherwise of actually uttering Voldemort's name, meanwhile robs the apotropaic device of its force.

In earlier generations scholars reacted by removing many of these objects from public view, putting them in the ‘Secret Cabinet’ of the museum at Naples or otherwise under wraps. […] More recently the fashion has been to deflect attention from their sexuality by referring to them as ‘magical’, ‘apotropaic’ or ‘averters of the evil eye’.

Commonly known as ‘ritual protection marks’, or even ‘witch marks’, an apotropaic image or symbol is a marking that is thought to create a ‘protection’ for the individual that created it – or for the area or object into which it was inscribed.