I saw this word used in another thread used to mean "parallel" or "analogy". (The practice of "redlining" was described as a "US corollary" to the British term "postcode lottery".)

The term originally comes from mathematics, where it means a proposition whose proof follows directly from the proof of another proposition. For instance, if I prove that the product of two odd numbers is always odd, then as a corollary it follows that the square of an odd number is always odd, since the square of any number is that number times itself.

By extension, the term has come to mean "a natural consequence or result", e.g. "this is the inevitable corollary of maintaining the formal powers at their present level". However, I haven't come across many examples of the word's use in the earlier sense. Any thoughts?

I was originally a mathematician so the original sense of the word is the one that I am most familiar with. The extension to mean "a natural consequence of" seems to be logical and sensible and is one that I see a lot.
I have sometimes come across the usage to mean "analogy" but it isn't one that I like as it conflicts with the meaning that I have for the word. In the other thread it was almost certainly just a momentary mistake but I have seen other instances, even in the press, where it is clear that the writer doesn't actually know what corollary means.

I suspect it comes from wanting to write "correlation".

This message has been edited. Last edited by: BobHale,