I assume the meaning of the name is a short way to say procedure,
much like of int in other OOP languages is shorthand for integer.
I ask this because the Ruby document site didn't addressed it in it's Proc page.
Santiago Trujillo
The Ruby Language Reference Manual (1998 by Yukihiro Matsumoto) refers to it as “procedure object”:
The
Procis the procedure object, which is the encapsulated block with context, such as local variables and stack frames.