A pheromone (from Ancient Greek φέρω phero “to bear” and hormone… ) is a secreted or excreted chemical factor that triggers a social response in members of the same species (i.e. fashion lovers). Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual (e.g. outfit), to impact the behavior of the receiving individuals (often ‘must have’).
…Modified excerpt from Wikipedia and honestly just a coincidence that I’m a graduated chemist 😉