I do not understand how allusions 'indirectly' mention something. I have looked at examples of allusions, and the allusions I have seen seem to directly mention something. The site below: http://www.softschools.com/examples/grammar/allusion_examples/115/ has a list of allusions. Can someone please explain allusions to me?
Here's an example of an allusion that seems to me to be fairly indirect:
Stanley is flying a kite on a cloudy day. Ollie walks up to him and says, "Caught any electricity yet, Ben?"
The allusion here is to Benjamin Franklin and more specifically to his famous experiment involving a kite and a key, conducted (so to speak) during a thunderstorm. In the allusion above, the kite, the key, the thunderstorm, the lightning, and the full name Benjamin Franklin all go unmentioned. To understand what Ollie is alluding to, you have to recognize that "Ben" refers to Franklin and then you have to recognize that Ollie is drawing a connection between Franklin's experiment and Stanley's kite flying on a cloudy day.
This is how allusions work in day-to-day situations—and often, as here, they only hint at the thing they allude to. You might argue that "Ben" is a direct reference to Benjamin Franklin; but taken at face value in the original sentence, "Ben" functions as a term of address to Stanley. In another situation, Ollie might use that same term of address to equate Stanley's behavior with that of, say, the leader of a band of killer rats. Ollie's statement doesn't make sense unless you get the allusion.