A Segulah1 is a particular act, recitation, or charm, which is said to aid a person (eg., in finding a mate, livelihood, or having children, etc.). It is based on what might be described as superstition, but which is practiced by many Jews, particularly among Orthodox groups, despite opposition from some based on the fear of violating the prohibition against Kishuf2.
1. For further reading, see this Jewish Treats post.
2. Kishuf is witchcraft or sorcery, which is prohibited by the Torah.