base note

In perfumery, this term refers to the heaviest molecules in a fragrance composition. These scents have the lowest volatility, meaning they evaporate slowly and provide the lasting foundation of a perfume's character long after the initial burst of top notes has vanished.

While often used technically by chemists and perfumers, the term is common in luxury marketing to describe the depth and longevity of a scent. It is distinct from the middle note (heart note) and top note in terms of both chemical weight and temporal presence on the skin.