What exactly WAS Apple Pascal?

[Zorin the Lynx <yakko@zorin.org>]

I was an Apple II user for many years in the 80's and early 90's, but I 
never actually found out exactly what Apple Pascal was, and references 
online seem to be nonexistent.

It seemed to be a disk format, operating system, and possibly a 
programming environment all built into one.. Hell, many utilities could 
copy files to and from "Apple Pascal" format disks, but what was the 
environment like?

Was it a full-featured Pascal compiler? An OS? A file format? Or all of 
the above? Did anyone here develop in it? What was it like?

I had exactly ONE program that used Apple Pascal, and that was SmartCom 
I, which drove my MicroModem IIe. (Note: This was the most useless comm 
program ever. It had no industry-standard file transfer protocols and 
had a goofy design. But hey, it got me on BBS's!)

A pointer to a FAQ or other document explaining Apple Pascal would be 
great too...

- A curious Z