The act of hallucinating; a wandering of the mind; an error, mistake or blunder.
A confident but incorrect response given by an artificial intelligence.
A sensory perception of something that does not exist, often arising from disorder of the nervous system, as in delirium tremens.
A delusionary or otherwise unachievable goal that one feels compelled to pursue.
A flickering light or lantern, especially over bogs, swamps or marshes, held by a supernatural creature who uses it to lure travelers at night to their demise.