Q From Ann Fisher: I have been unable to find a definition for the word oneirodynia anywhere. Perhaps you might help?
A No problem, though it is a rare word, and needs a larger dictionary than the average to be sure of finding it. It comes, like other words starting in oneiro-, from the Greek oneiros, “a dream”. So we have oneiromancy, foretelling the future by interpreting dreams, and oneirism for a dream-like hallucination in a waking state. In oneirodynia it’s paired with a suffix that comes from the Greek odyne, “pain”. It refers to troubled sleep, nightmares, perhaps sleepwalking.