Where the heck did the terminology for the subscript 0 come from?

[Shooters]

Where did the terminology for the subscript 0 (usually used in engineering and mathematics to denote a starting or initial condition) come from? Let's say you have a variable Po; one way to say it sounds like "pee-not". But what is the exact spelling?.....is it "not"? And where did this terminology come from?

 

[PrincessGuard]

"Naught" is old English for zero.

 

[gopunk]

http://mathworld.wolfram.com/Naught.html

 

[Shooters]

Ahh, thanks guys.