reference
reference to another work
picture citation
reference to an image in the arts and literature
quotation
repetition of one expression as part of another one
Beowulf and Middle-earth
parallels of the Geatish legend in J. R. R. Tolkien's works
Nixon goes to China
political metaphor referring to Richard Nixon's 1972 visit to China
Film quote
reference to a film by textual quotation or allusion to a scene
musical quotation
incorporation of a relatively brief segment of existing music in another work