There are at least three bands with the name Noumenon (or some variant thereof). 1. nou·me·non noun - a posited object or event as it appears in itself independent of perception by the senses. alternate definition: nou·me·non state of mind - the experience of music listening where your brain feels like it will explode for two reasons. One - because the technical nature of the noise penetrating your eardrums is of an intricacy that would have made Nikola Tesla shit himself.