Sillage, a French word meaning "wake," was originally applied to the way waves radiate around a passing boat. In perfumery, it is used to describe a similar phenomenon - how a fragrance wafts or leaves a trail around the wearer. Sillage will differ from person to person and is impacted by the characteristics of the wearers skin, the ambient temperature of their environment, and whether they are in motion. Skin characteristics can also impact the general impression of the fragrance so you may notice a difference between your sillage and the sillage of a friend wearing the same perfume.