A burnt quality imparted to something by heating, specifically an odour or taste of charred organic matter; volatile or oily compounds responsible for this. Also: an organic residue left after distillation. Also in extended use.
Late 16th century; earliest use found in George Baker (1540–1612), surgeon. From post-classical Latin empyreuma from ancient Greek ἐμπύρευμα live coal covered with ashes, used for rekindling the fire from ἐμπυρεύειν to set on fire (from ἐμ-, variant (before a labial) of ἐν- + πυρεύειν to light a fire from πῦρ fire: see pyro-) + -μα.