triple combo and double combo relates to how many "attacks" you pull of.

Some chase abiliities chase "HIGH COMBO" and that's usually 10.

so if you get 10 "attacks" in a row. That becomes a 10 hit combo and you will trigger this "CHASE HIGH COMBO" skill.

essentially, when you battle, on the left will be skill combos. and on the right will be number of hits. Chance of triple combo means chance of 3 hits.