What is the difference between the terms percolation and brewing in English? Percolation and brewing seem used quite interchangeably in English, in many contexts, but not all. For example, I can often see "percolation time" in technical documents or Wikipedia entries, but often hear "brewing time" as well.

Is there any usage guidelines for these words in the English coffee world?

The problem is that percolation and brewing are not just about coffee: Both terms are generic. Percolation sounds more technical and focusing on liquid getting through a filter. Brewing seems focusing more on "solid into hot water", without involving necessarily a filter. This lets me think the words usage can be made quite accurate.

Please note that the scope is "restricted" to English, as percolation is a Latin word, and it seems usage differs in English.
Brewing is a part of every coffee preparation method: it's the time when the water (or steam) is in contact with the grounds. It is a generic term.

Percolation however, would only be used when making percolator coffee. You would not talk about percolation time when making espresso, for example. I would not use it as a generic term.