1A mysterious light supposed to be seen floating or flickering in the air around a corpse, in a graveyard, etc.; a phosphorescent light superstitiously regarded as an omen of death, a corpse candle.
2A light kept burning in the room of a person who is dying or has recently died. Now rare.
Origin
Late 18th century; earliest use found in Robert Burns (1759–1796), poet. From death + light.