These terms refer to the strength of the fragrance, specifically, to how much high-grade alcohol or water is added to the fragrance oils. Perfume (known to be the most concentrated form you can buy) has 18-25% perfume oil dissolved in alcohol. Any mixture with a lower proportion of oil to alcohol is an Eau (water). Eau de Cologne – usually 3% or less perfume oil Eau Fraiche – 3 -5% perfume oil Eau de Toilette – 6-12% perfume oil Eau de Parfums – 13-18% perfume oil Perfume or Extrait – 18-25% perfume oil