There’s no ISO standardized definition for variable. People use that word with all kinds of meaning.
Waaaait a minute… isn’t it called a variable because the contents are, you know, variable?
This is needlessly obtuse. The definition of the word is that it’s non-constant. There isn’t an ISO definition of the word no, but there are many reputable dictionaries out there that will serve as an alternative.
Well, starting with the definition from algebra, where it’s not something allowed to vary…
I guess more people know about math than use imperative programing languages.
Except that’s exactly what it is allowed to in algebra.
Sure, in most equations you solve in early algebra school there is only one possible value for the variables. But in many equations there can be multiple, or even infinite. It’s an unknown, and the contents can vary (depending on other constraints, ie. The rest of the equation(s)).