Stage order [& definition if needed]

Launch [>100m elevation gain]

Max Q

Main Engine Cut-Off (MECO)

Stage Separation

Second Stage Ignition

Booster Boostback Burn

Second Stage Engine Cutoff (SECO)

Booster Ocean Landing

Second Stage Landing

For all of the above stages, Starship has to complete the stage successfully before failing. For example, if the second stage separates succesfully but then the engines fail to light, this resolves to "stage separation".

Failure is defined as anything that prevents the second stage from executing the planned mission profile. Loss of the booster after separation is not considered a failure for the overall mission. If things get hairy but the second stage limps its way to the desired target, I'll call that a success.