The (Unfinished) PDE Coffee Table Book

...the latter

> I see no definition for 'PDE'

Please see the second sentence on the page:

> The vision was 100 2-page spreads, each one giving exactly the most useful possible starting information about a different partial differential equation, with beautiful color illustrations.

It’s on a mathematician’s homepage. PDE is about as familiar an acronym in that field as, say, “SQL” is in tech.

Assuming you had your math education in English. I've only studied CS, but I've had my fair share of math at university and yet most of the names are not recognizable (the concepts are, but it takes a moment to grasp it) because my lectures were in German.