'To open,' as in Revelation 9, signifies communication and conjunction.

(Riferimenti: Apocalypse Explained 537)

777. That 'bird' means spiritual truth, 'flying thing' natural truth, and 'winged thing' sensory truth, is clear from what is said above, as also is the fact that truths are in this way different. Sensory truths, which come through seeing and hearing, are called 'winged things' because they are outermost. 'Wing' has a similar meaning when applied to other things.