Notes in perfumery are descriptors of scents that can be sensed upon the application of a perfume. Notes are separated into three classes; top notes, middle/heart notes, and base notes; which denote groups of smells that can be sensed with respect to the time after the application of a perfume. These notes are created carefully with knowledge of the evaporation process and intended use of the perfume. However, each class of notes is not as easily sensed at a certain time they can alter the smells of another note class. For instance, the presence of a certain base or heart notes will alter the scent perceived when the top notes are strongest, and likewise the scent of base notes in the dry-down will be often be altered depending on the smells of the heart notes.

The idea of notes are used primarily for the marketing of fine fragrances. They are used less occasionally by perfumers to roughly describe scents or the perfumery process to layman.