ef·flu·vi·um 
(ĭ-flvē-əm)
(ĭ-flvē-əm)n. pl. ef·flu·vi·a (-vē-ə) or ef·flu·vi·ums
1. A usually invisible emanation or exhalation, as of vapor or gas.
2.
a. A byproduct or residue; waste.
b. The odorous fumes given off by waste or decaying matter.
3. An impalpable emanation; an aura.
[Latin, from effluere, to flow out; see EFFLUENT.]
ef·fluvi·al adj.