I am not a physicist but I've started studying the subject and noticed that terms like "random", "randomness", "randomly" are widely used when talking about nature. For example, random movement of atoms, random fluctuations, random path of an electron etc.
My question does not concern any of these examples themselves.
What I would like to know is whether physicists use the term "randomness":
That is, whether physicists believe that true randomness actually exists in nature: Do physicists believe that (in some cases) something that is in a certain state X, is so not due to some cause (or a collection of causes) that preceded it and caused it to be in that particular state X rather than in some other possible state Y. In other words do physicists believe that causality is not a rule.
Do physicists use the term "randomness" as simply a shorter way of saying:
"we know that there must be a trillion things that caused this state X rather than this other possible state Y, but because the number of things that constitute that cause is so great, we can never know it or grasp it in its whole as humans, so in those cases we'll call it 'random' for lack of a better word, but we don't actually mean 'random' in the literal sense of the word".
EDIT: I want to know how the term is used by physicists, so that I may know how to proceed with the study of the subject. I'm not interested in opening a discussion about whether nature actually is (or not) non-deterministic sometimes.