@b2d9fca2 

> Even the examples they give for the secondary definition that matches yours are archaic idioms.

When a definition is considered archaic it is explicitly listed as such.. These are modern idiomys, they just have been around a while. But they were also examples, so that doesnt mean much anyway. When a phrase is archaic it is labeled as such, these are clearly not archaic definitions according to the dictionary.

> If someone says "I dropped the check in the mail yesterday.", then no reasonable person would understand that to mean anything other than "the day before today."

Thats because as humans we are remarkably good at discerning the definition in use by context.

Here is a non idiomatic usage of this definition:

"No one wont wear yesterday's fashion to the Oscars!"

Not an idiom, clearly not archaic, and used to mean "the recent past" clearly and no one in their right mind would think they ment "the day before today" in this context.