This word appears three times in quick succession, in relation to “every unclean spirit,” “every unclean bird,” and “every unclean and detestable beast.” The fact that it is mentioned three times puts emphasis on the term; the Holy Spirit wishes us to pay attention to it (for John could have used commas instead of the word “haunt”). The term translated as “haunt” is well-known throughout Scripture and has two meanings: 1) the divisions of the night into “watches” (Matthew 14:25); 2) a place of guarding, that is, “prison” (Matthew 14:3). The latter meaning is by far the more common of the two possibilities and clearly the better one in this verse. Fallen Babylon is a prison.
2 And he called out with a mighty voice, “Fallen, fallen is Babylon the great! She has become a dwelling place for demons, a haunt for every unclean spirit, a haunt for every unclean bird, a haunt for every unclean and detestable beast.