[Question] What do the reported levels of protection offered by various vaccines mean?

Pfizer is supposed to be “95% effective”. Does this mean:
1. There is a 95% reduction in your odds of getting COVID (as measured by the gold standard, which I believe is aserological test?)
2. There is a 95% reduction in your odds of testing positive for COVID
3. There is a 95% reduction in your odds of getting symptomatic COVID
or
4. Something else?