To achieve a pleasant balance, the fragrance notes are classified as musical chords: top notes, heart notes, base notes.
These notes make up the accord of the perfume, they are its personality. Each note reflects the volatility of the perfume, or how quickly it evaporates. Top notes fade faster while base notes linger longer.
Perfumers use the olfactory pyramid to represent the fragrance notes of a perfume. Each ingredient is characterized by its degree of evaporation and persistence over time.