EFFLU'VIUM, noun plural effluvia. [Latin from effluo, to flow out. See Flow.] The minute and often invisible particles which exhale from most, if not all terrestrial bodies, such as the odor or smell of plants, and the noxious exhalations from diseased bodies or putrefying animal or vegetable substances.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI