effluvium

This term carries a strong sensory association with decay and toxicity, often evoking a visceral reaction of disgust. It is typically used in formal, scientific, or literary contexts to describe noxious gases or liquid waste that drifts or flows from a source. In historical or philosophical contexts, the word shifts from a physical smell to a theoretical substance. It describes an invisible flow of particles believed to transmit properties between objects, reflecting an archaic understanding of physics and chemistry.