Subtile or invisible emanation; exhalation perceived by the sense of smell; especially, noisome or noxious exhalation; as, the effluvium from diseased or putrefying bodies, or from ill drainage.
a foul-smelling outflow or vapor (especially a gaseous waste)
shedding, especially of hair.
effluvium, a flowing out], an outflow, which may pertain to sudden, severe hair shedding
Effluvium refers to an outflowing or shedding, or exhalation or emanation, particularly one that is noxious or toxic.