Seibel2005, §6. Variables
Scope and Extent are complimentary terms. Scope refers to the space where variable is visible, but Extent refers to the time the variable is valid for.
Combination of indefinite scope and dynamic extent is frequently referred to by the misnomer dynamic scope.
Rust lifetimes are not about object creation/destruction but about how long the object is available at the given location—Rust lifetimes represent extent explicitly.