What types of indirect references are and aren't allusions?

Question

In school I learned that allusions are indirect references.

Often my teachers would give examples in the form of references to well-known literary works.

If I say "I can read the writing on the wall", I'm making a reference to the hand of God writing a prophesy of doom at the feast of Belshazzar in the book of Daniel, and comparing it to my own situation.

Or if I throw you a can of Sprite and say "here, obey your thirst", I'm alluding facetiously to the Sprite commercials from the late 90s.

These are the type of indirect references that I'm sure are allusions. But if the purpose of allusion as a poetic/rhetorical technique is to make the reader feel kinship through referencing the things we all know about, then I'm curious whether other indirect references would qualify as allusions.

A couple examples I'm curious about:

Isn't it romantic? / Moving shadows write / The oldest magic word

—"Isn't It Romantic" by Rodgers & Hart

"The oldest magic word" is referring indirectly, and via a metaphor, to love. We all know that love is ancient and magical. Would this qualify as an allusion?

"I know when that hotline bling / That can only mean one thing"

—"Hotline Bling" by Drake

The "one thing" that Drake's phone ringing late at night can mean is that the girl he's talking about is DTF. We understand what he's referring to and he doesn't have to say it directly. Does this qualify as an allusion?

Answer 1

Britannica.com gives the following explanation:

Allusion, in literature, an implied or indirect reference to a person, event, or thing or to a part of another text. Most allusions are based on the assumption that there is a body of knowledge that is shared by the author and the reader and that therefore the reader will understand the author’s referent. The word allusion comes from the late Latin allusio meaning “a play on words” or “game” and is a derivative of the Latin word alludere, meaning “to play around” or “to refer to mockingly.”

In traditional Western literature, allusions to figures in the Bible and from Greek mythology are common. However, some authors, such as the Modernist writers T.S. Eliot and James Joyce, deliberately used obscure and complex allusions in their work that they knew few readers would readily understand.

William Irwin in his article published in The Journal of Aesthetics and Art Criticism says

(...) Allusions, then, to be understood and interpreted correctly must accord with authorial intent.

What about connections between texts that readers make independent of authorial intent?

Such connections are what we called accidental associations. We do not want to limit the reading process to recognizing authorial intent, but we do want to distinguish between readings that accord with authorial intent and those that do not. As Hermerén says with regard to his own definition of allusion, “The definitions outlined here do not exclude that literary critics take an interest in what a text suggests to more or less well-educated readers, regardless of what the author intended.”5 We, as readers, can generate much aesthetic value on the basis of our own readings. The text may suggest many things that the author did not actually intend, but that an ideal, or merely reasonable, reader is correct to notice. There is no harm in taking notice of these things as long as we do not incorrectly attribute them to the author or his or her text. They are, properly speaking, our reading, which in fact may be a misreading.

Based on Brittanica and Irwin's explanations, I would say that yes, your examples qualify as allusions i.e. the authors intended their readers/listeners to make mental connections with what came before.

More examples, from everyday speech and literature here, and bilical allusions here