What does it mean?

[Tento]

When a bio has AACT beside an element, what does it mean?

 

[Alternative]

AACT means Additional Approved Canon Techniques. They're techniques which were shown in the manga after the jutsu list was written, and are added as they're shown. You'll need training in them to use them, but if you've got the training for them, and more are added, you get them auto.

 

[Tento]

Oh, thanks, couldn't find that anywhere.