This thread seems to be about semantics and word definitions - but aren’t we focused on the wrong word?
I think what people want to know is if acceptances at different schools are correlated. The underlying question is something like “if I apply to two schools for which I have a 50% chance, do I have a 75% chance of getting in to at least one?” Assuming access to the data, you could take the population of students with a 2400 SAT, and see which Ivies they get in to. Maybe about 30% would get in to each Ivy. Then you would want to compute the correlation between those n data sets of accepted students per Ivy. They would obviously be partially correlated. So the chance of getting in to either of 2 with a 2400 wouldn’t be 1 - 70%^2 = 51% - it would be less.