A lexical environment for evaluation at some position in a program is that part of the environment that contains information having lexical scope within the forms containing that position. A lexical environment contains, among other things, the following:
The lexical environment that is active at any given position in a program being semantically processed is referred to by definite reference as ``the current lexical environment,'' or sometimes as just ``the lexical environment.''
Within a given namespace, a name is said to be bound in a lexical environment if there is a binding associated with its name in the lexical environment or, if not, there is a binding associated with its name in the global environment.
18.104.22.168.1 The Null Lexical Environment