In one hour; that is, suddenly. The term denotes rather the surprisal of this judgment, than the short space of time within which it should be effected.
Related Commentaries of Revelation 18:17
Revelation 18:17
17 For in one hour so great riches is come to nought. And every shipmaster, and all the company in ships, and sailors, and as many as trade by sea, stood afar off,