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.
184.108.40.206 The Global Environment
220.127.116.11 Dynamic Environments
18.104.22.168 Lexical Environments
22.214.171.124 Environment Objects