When a word or idea is activated, as by encountering it in the environment, nearby words are also raised to some level of activation, and thus become more likely to be used.
Connections can be semantic, syntactic, associative, etc.
Whether the word was ever used by Freud would be rather easy to check, as I think concordances exist. I have not consulted dictionaries besides those mentioned. I cannot find it in the Canadian Oxford dictionary. If my memory serves, orapedia is supposed to be the accumulated knowledge that one has in one's memory. If I am incorrect, then I apologize, but I'm pretty sure that this is what orapedia means.