What exactly qualifies for a triggered effect? In a recent game a card came into play with the ability to cancel triggered effects and we were not sure what that entailed , any help would be appreciated.

More or less, it's any ability that you trigger yourself, anything that says "<phase>:", "Any phase" or "Response:" is a triggered ability.

Passive Abilities are not triggered.

That makes more sense than what my opponent said - he told me it only worked with cards that say triggered effect on them and i dont have tons of cards but none of my cards say as a "triggered effect". Thanks for the quick response and happy thanksgiving!