A binding is an association between a name and that which the name denotes. Bindings are established in a lexical environment or a dynamic environment by particular special operators.
An environment is a set of bindings and other information used during evaluation (e.g., to associate meanings with names).
Bindings in an environment are partitioned into namespaces. A single name can simultaneously have more than one associated binding per environment, but can have only one associated binding per namespace.
188.8.131.52 The Global Environment
184.108.40.206 Dynamic Environments
220.127.116.11 Lexical Environments
18.104.22.168 Environment Objects