The environment of a procedure is the complete set of variables it can access; the state of the procedure is the set of values of these variables.
A binding is an association of a name with a storage location; we use the verb bind for the creation of a binding and say a variable is bound to a location. An environment provides a set of bindings for all variables.
An assignment, e.g. pi := 3.14 , changes the state of a procedure but not its environment.