Allusion is a brief reference to a person,
event, or place, real or ficticious, or to a work of art. Casual
reference to a famous historical or literary figure or event.
An allusion may be drawn from history, geography, literature, or religion.
Example:
Stephen Vincent Benet's story "By the Waters of Babylon" contains a
direct reference to Psalm 137 in the Bible.
Resources:
Bible Literacy Project resource for locating Biblical allusions.
Allusions - Cultural, Literary, Biblical, and Historical: A Thematic Dictionary