From the Latin "wave of the sea", it is a particular register of the organ, of the oscillating family. It is made up of two identical pipes, one of which, however, is tuned slightly lower than the other. The "phase shift" between the two frequencies produces a particular physical phenomenon which generates the characteristic "waving" effect of the sound.

Subject : Incense, Vanilla, Patchouli, Tonka bean, Benzoin, White musk
Against subject : Marine notes, Myrtle, Nutmeg, Geranium
Base : Artemisia, Myrtle, Cedar, Jasmine, Eucalyptus