Today, I read a couple of discussions in Cross Validated, and these two words popped up quite a bit. I do not know how to differentiate them in usage (especially writing) because they are quite interchangeable to me.
In statistical contexts, they’re interchangeable. (See, e.g. Causality (also referred to as causation, or cause and effect) and Causation (Alternative titles: causality, cause and effect).)
Usually the “right answer” for a given context comes from an ossified expression like “correlation is not causation” or “Granger causality”.