What do you call a word that is used overtly to mean something besides its actual meaning?

Question

Inspired by this q/a and the comments on it.

I'm not even sure how to describe this, so my research hasn't yielded much.

Take for instance the figure of speech "A million little things", which doesn't really mean literally one million things, but rather "a heck of a lot of little things".

What would you call "million" in this context? It has a meaning of its own, but it's used to just mean "a lot" rather than "a million". Bonus points I guess if the word can also be used to describe words without a meaning, like "gajillion".

Sample sentence: "In this context, 'million' is a ____, used to mean 'a lot'."

I may be muddying the waters here, but I think other examples would be words like "brother", which is sometimes used to refer to non-brother relationships, and "peanuts", which can be used to refer to non-peanut things that are perceived as insignificant.

With the latter two examples, "slang" seems appropriate, but calling "million" "slang" seems to be off the mark.

Answer 1

This is an example of the rhetorical device of hyperbole:

extravagant exaggeration (such as "mile-high ice-cream cones")

From Merriam-Webster

The word is from Greek and means excess. It has come to mean a figure of speech that uses extreme exaggeration for emphasis or to make a point.

The word originally meant "to throw over":

"obvious exaggeration in rhetoric," early 15c., from Latin hyperbole, from Greek hyperbole "exaggeration, extravagance," literally "a throwing beyond," from hyper- "beyond" (see hyper-) + bole "a throwing, a casting, the stroke of a missile, bolt, beam," from bol-, nominative stem of ballein "to throw" (from PIE root *gwele- "to throw, reach"). Rhetorical sense is found in Aristotle and Isocrates. Greek had a verb, hyperballein, "to throw over or beyond."

From the Online Etymology Dictionary

Answer 2

There are two different words for two different examples that you have provided in your description.

"Million" in drama series A million little things is used in nonliteral (or non-literal) sense.

Non-literal according to Oxford dictionary is

Not using or taking words in their usual or most basic sense.

and according to thefreedictionary.com

not literal; figurative

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Whereas, the word gajillion is used analogically to denote some imaginary large number. Wikipedia states that numbers like gajillion are Indefinite and fictitious numbers.

Excerpt from wikipedia:

Words with the suffix -illion (e.g. zillion, gazillion, jillion, squillion) are often used as informal names for unspecified large numbers by analogy to names of large numbers such as million,billion and trillion.

So, gajillion is used analogically to denote some imaginary unspecified large number in the link that you have provided.

NOTE: The word Non-literal also cover analogical under its umbrella. So, if you not want to use to different words, then you can just use just Non-literal.