The As reference article from the Simple Wikipedia on 24-Jul-2004
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As

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As as a connective to compare the similarities of two concepts. Like "like", this is called a simile. But as is more often used in idioms specific to English:

Usually, one concept is more abstract and the other is more concrete - and the connective is intended to be more general than just one situation. When this is so, using "as" may imply that a conceptual metaphor is in effect in other statements:

In other words, you can say more generally what an idiom or metaphor says: for example, "battle of the sexes" is both a metaphor and an idiom that suggests "love as war".

Because of this power, you can restate an idiom or metaphor in a way that makes it clear what it means, and what it might assume.