Meteor smashes/spikes can be meteor cancelled by jumping or using your third jump after the one second that you are frozen during a meteor spike/smash. Jumping after a meteor is also called a meteor jump. Spikes can't be cancelled (one of the reason Falco's Dair is feared.)
The way you can tell if an attack is a meteor smash is if it has a slight glow before you use it, like Gannondorf's Dair or Mario's Fair.