[oconnor663]

I propose that we refer to the (potentially non-lexical) scope of a variable as its "zone". Active variables would thus be said to be "in the zone".

[withoutboats]

This touches on some interesting history: lifetimes were originally (in other PL literature) called "regions" (MS Research's Verona also uses this terminology). Lifetime was chosen because an analogy to time seemed more intuitive for this concept than an analogy to space - space analogies being usually used for sections of program memory, rather than periods of program execution.