Allusion has got to be the best literary element known to Humankind! It's more than cool, and, by the way, you know what it is, you probably just didn't know it had a name.
The word "Titanic' is an allusion to titans.
The word Beatles alludes to the musical beat known in the 60s as the backbeat. The lyrics "Lucy in the Sky with Diamonds" is an allusion to LSD. John Lennon, the writer, swears that the line comes from a drawing his child drew; but, listeners say the line reminds them of LSD, a drug. In other words, the allusion can be unintentional. I..doubt it in this case, though.
Blowin' in The Wind by Bob Dylan
"Yes n' how many seas must a white dove sail Before she sleeps in the sand?"
Since the dove is a common symbol of peace, the obvious meaning of this question is: "how long will men continue to war with one another?" But it may also allude to Genesis 8:8: "Also [Noah] sent forth a dove from him, to see if the waters were abated from off the face of the ground: But the dove found no rest for the sole of her foot..." The dove can not rest--sleep--in the sand because the consequence of man's sin--the flood--is still upon the earth. Dylan's question, then, may be: "When will man cease to sin so that the consequences of his sin--in this case the brutality of war--will recede?"
The Times They Are A-Changin' by Bob Dylan
"And the first one now Will later be last."
An obvious reference to Matthew 19:30: "But many that are first shall be last."
That song is about slavery albeit indirectly considering the life of it's composer. I often wondered about the "Saved a wretch like me" part. Didn't think it was just a general allusion to fundamentalism and the iniquity of mankind.
Allusion: Part of a system of reference that triggers an association or echo in the reader. Familiar elements drawn from a shared cultural context, borrowings from other literary works enable the poet to broaden the context and deepen the meaning of his/her work. Allusion demands and relies upon cultural literacy: a shared understanding of literary traditions and culture. It assumes a common bond of knowledge shared by writer and reader.
Allusion = reference(s) to events, characters, myths, history, other poems, plays.
An allusion shares something with its source: words, letters, orthography, meanings, syntactical relations, whatever...the idea of "shared information,"
When Wordsworth writes in the Prelude, "The earth is now before me" (I.14 in both the 1805 and 1850 editions), he is clearly alluding to Milton: "The World was all before them, where to choose/Thir place of rest, and Providence thir guide" (Paradise Lost, XII.646-47).
The single most famous line in English literature, "to be or not to be" from Shakespeare's Hamlet, if stripped down to its syntactical pattern of Infinitive -- conjunction -- negative adverb -- infinitive: "to go or not to go" is recognized immediately as an allusion to Hamlet's soliloquy.
Eliot's "April is the cruelest month" is universally recognized as an allusion to Chaucer's "What that Aprille, with his shoures soote". Eliot's words remind the reader of Chaucer's words. This is not to say that Eliot purposely altered Chaucer's words. We don't know that.
It is possible to allude to a genre, an author, a specific work by borrowing it form, such as sonnets, odes, blank verse, heroic couplets, and haiku. The use of kigo or seasonal references, for example, is the haiku tradition.
Please note, I found the following information on "allusion" on the Web. And, by mistake, I deleted the source sites. Sorry about that.