The default contexts for looking up symbols:

The symbol Integrate can be found because it is in the "System`" context:

If a symbol with a given name is not found in one of the contexts in $ContextPath, it will be created:

It is created in the context given by $Context:

Turn off the message for new symbol creation:

$ContextPath must always be a list of strings:

Both simple and compound contexts can be included in $ContextPath:

Add Developer` context to the context path:

PackedArrayForm is a command in the Developer` context that can now be used directly:

Restore the previous context path:

Symbols on $ContextPath are found before symbols in $Context with the same name:

System`Grad is found because "System`" is by default a member of $ContextPath:

Contexts on $ContextPath are searched in order:

Reversing the order of "cont1`" and "cont2`" changes which x is found:

If an input symbol contains context marker (`), $ContextPath is ignored:

The variable x in the current context is found:

However, inner`x is not appended to "outer`", which is on the path, to form outer`inner`x:

BeginPackage changes $ContextPath to consist of "System`" and the package context:

EndPackage restores the previous value of $ContextPath with the package context prepended:

Begin does not alter the value of $ContextPath:

Neither does End:

An active context alias cannot be added to $ContextPath: