The Export structure describes the exported output values for a stack.
Export
The stack that contains the exported output name and value.
The name of exported output value. Use this name and the Fn::ImportValue function to import the associated value into other stacks. The name is defined in the Export field in the associated stack's Outputs section.
Fn::ImportValue
Outputs
The value of the exported output, such as a resource physical ID. This value is defined in the Export field in the associated stack's Outputs section.