Cutting Words says (PHB, p. 54, emphasis mine):
When a creature that you can see within 60 feet of you makes an attack roll, an ability check, or a damage roll, you can use your reaction to expend one of your uses of Bardic Inspiration, rolling a Bardic Inspiration and substracting the number rolled from the creature's roll.
Now, if a bard uses Cutting Words in order to alter the damage roll of a creature throwing some AoE at the party (a wizard casting a Fireball, a dragon's breath weapon, etc.), does it "cut" the damage done to each target affected by the AoE effect?
That would seem pretty powerful, considering that a 5th level Lore bard with a charisma of 18 can use Cutting Words once per round, up to 4 times between each short rest, using d8s to "cut" the damage done by those effects.