That "thermocouple" key is the Option. I remember reading that Apple started using symbols (The same ones that appear in the menus) on some "higher-level" keys because they may have different uses in different countries, or even different names. And the story as I under stand it, is when Apple release the first ADB full Size KB with F keys, they added "alt" over the option to help PC users cope, considering that the "command" uses the spot that PC traditionally carry the "alt". Also, I heard they added it so people would know where the alt key when they used to ship Macs with PC's on a daughter card like the Performa 630/DOS. Its just become habbit, personally, I'd like to see the "alt" go away, and have us call "command" "open Apple" as we all learned it in school on the Old Apple IIs. (Remember Open Apple, Closed Apple). In fact, I've always called it "Open Apple" and always. I remember reading some documents about developing on a Mac in like 2001, and Apple suggest that developers use the folowing nomenclature:
Folder - instead of Directory
Apple Key - Instead of Command
Of course It has been a while, so a can't remember any more. These are just the ones that got stuck on the roof of my mind.
TEG