A Lookup consists of a scope group name which indexes into an array of scope names or a single scope name. When a lookup is resolved/expanded, all the indexed scopes are searched. For example, given the following Lookup definition,

{ food: ['vegetables', 'fruits'] }  // assumed the 'vegetable' and 'fruits' scopes exist.

when this term is resolved/expanded, it will search over the 'vegetables' and 'fruits' scopes.