principalities of evil
The rebellious angels, cast out of heaven, were in Saint Paul's day believed to dwell "in the high places" or "in regions above" (Ephesians 6, 2).
Like the faithful angels (Ephesians 1; Colossians 1), they preserved their respective ranks in the fallen state.
Of the evil spirits three classes at least are expressly mentioned in the New Testament (1 Corinthians 15; Ephesians 6; Colossians 2).
In Jude 1, "principalities" denotes rather the dominion or province or their former power before the fall.
New Catholic Dictionary